The best way to learn about the Assignments module is to consider a complete cycle of activity. A typical cycle consists of the following activities:
The teacher posts an assignment, which is delivered to all students in the classroom.
A student opens the assignment, does the work, and sends back a reply that contains the completed assignment. This reply is seen only by the teacher(s) in the classroom.
The teacher receives and reads the student's work, and sends back some sort of acknowledgement, which often includes a marked-up copy of the work the student submitted along with a grade.
The following sections examine this cycle in more detail.
Teachers can post a new assignment by clicking on the New Item button that appears on the topic index page seen when you first enter the module:

The above screenshot shows the teacher's view of the Assignments module, immediately after entering the module from the classroom's Main Menu. The commands at the top of the page are pretty much the same as those found in the Class Discussion module. A difference is that in the Class Discussion module anyone can start a new topic, but in the Assignments module, only the teacher can start a new topic. The "topics" are really assignments - work for students to complete. Clicking on the New Item button yields:

Notice the additional choices in the Attachments area. These are necessary to support the use of Hot Potatoes multiple-choice and short answer exams within the Assignments module. See Online testing: Hot Potatoes exams for more information.
Once a new assignment is posted it will appear on the topic index:

Unless you marked the message as teacher-hidden when it was posted, the new assignment will be distributed to all students in the class.
The topic index looks much like the topic index for the Class Discussion module. However, for the teacher, there is another layer of organization to the Assignments module. When you, as the teacher, click on the assignment, you'll see something like this:

In the above illustration, you begin to see what makes the Assignments module different from the other discussion modules. When the teacher clicks on an assignment from the initial list, he is brought to a page that lists all of the students in the class. Each student name on the list is a hyperlink, and behind that link will be all of the messages that the student and the teacher have (privately) exchanged regarding the assignment.
The numbers in parentheses next to each student's name indicate the number of messages that have been exchanged regarding this particular assignment. In the above illustration, all of these numbers are (0), since no students have responded to the assignment. You'll have a clearer idea of how this works as you read through the rest of the assignment "cycle" in the following sections.
For now, note to read an assignment you just posted, you need to click on the subject of the assignment as shown in the above illustration.
The teacher can click on the subject of the assignment, "Assignment #1 - due May 3 by 2PM" in the above example, to read the assignment he just posted. You should get into the habit of doing this immediately after posting an assignment, since you'll find that the teacher cannot delete an assignment after a student has posted a reply.

As shown in the above illustration, once a student submits work for an assignment, you will no longer be able to delete it. This was done by design, since the Assignments module can hold many hours of work produced by many students.
As the teacher, you should get into the habit of checking an Assignment for correctness immediately after you post it to the Assignments module. If you want to retract it, you can delete it (possibly after copying it to Manhattan's clipboard - see section Manhattan's Copy and Paste Commands) before students have had a chance to respond. After one or more students have responded to an assignment, you can no longer delete it (there, I said it again!)
Once an assignment has been posted by the teacher, the assignment appears on the topic index for all students in the class:

After clicking on the message, the student reads the assignment in pretty much the same way he reads other messages:

After opening the assignment, the student can print it along with any attached files that are part of the assignment. After completing the work, possibly by creating a file with a word processor, the student opens the assignment again and clicks on the "Reply" button:

The student sees the usual Manhattan compose message form. While the student could type the answers directly into the message, more typically he will attach a word processing document (or any other type of file) that contains the solutions.
After sending the message, the student's view of the topic index becomes:

From the student's point of view, the Assignments module looks just like the Class Discussion module. Again the major differences are that a student can't start a new topic - those are assignments posted by the teacher, and messages are seen only by the student and the teacher(s) of the class - this is NOT a public forum!
As described in Did you get my message?, the author of a Manhattan message can click on the "?" next to the message or on the Info button seen while reading the message when the recipients have opened the message. This basic principle holds true for the Assignments module. After posting a reply to an assignment, the student can come back at any time to check to see exactly when you've opened the message for the first time.
Let's now change hats and go back to the teacher's point of view. When entering the Assignments module, the teacher now sees something like this:

After clicking on the assignment, the teacher sees:

As mentioned earlier in the "cycle", this page lists all of the students in the class. The numbers in parentheses indicate the total number of messages exchanged with that student regarding this assignment. As throughout Manhattan, a red star is used to indicate there's at least one unread message behind the link.
Clicking on "Betsy Answer" yields the following:

You're now looking at a dialog between yourself and Betsy regarding this assignment. Listed so far is the original assignment and Betsy's reply, which contains her work for that assignment. Clicking on Betsy's reply yields the familiar page:

Note the additional information circled in red in the above illustration. If you chose to 'lock the attachments' to the assignment, this elapsed time information can tell you exactly how long the student took to return his work, starting from the time he first unlocked the attachments - see Online testing: using locked attachments for more information.
Since Betsy submitted her work as an attached Word file, you next need to open that file. Clicking on the file name link should download and open the file within Microsoft Word:

Exactly how Word opens the file depends on the web browser you are using (Internet Explorer, Netscape, or other), and what version of Word you have on your computer. In any case, the idea is to view the student's work in Word, and edit the document any way you see fit.
Word has a number of features you can put to good use when correcting student work. You can, for example, put your comments in a different font and/or a different color. Word's ability to insert comments (look under the Insert menu) and the "highlighting" feature are also very useful.
After marking up Betsy's answer, select Save As from the File menu to give the file another name. If you simply use Save, the file will usually be saved with a very long and odd name in a temporary directory on your computer. Use Save As to save the file and remember which folder you put it in! You'll find that you do not need to give each marked-up student assignment a different name. There is no need to store dozens (or hundreds) of your responses to student work on your personal computer. That's Manhattan's job! A good idea is to always call the work you're returning to students return.doc and put it in your "My Documents" folder. That way, the steps for returning work to students will always be the same.
When you are ready to send a graded reply back to Becky, get back to the message she posted, and click the Reply button:


That completes the "cycle". When Betsy logs into your classroom again, she'll see a red star on the Assignments module button in the Main Menu. Upon entering the module, she'll see:
The assignment you posted
The work she submitted
Your graded reply
As the teacher, you'll also see all of the above - for every assignment you posted during the semester, and for every student in the classroom. When used to its full potential, Manhattan keeps a complete record of all assignments for your entire course.