If you don't have enough virtual memory to run all the applications you want to run, then pull down the colorful apple menu (upper left hand corner), select the "Control Panel" submenu, and select from it the entry called "Memory". Reset the virtual memory to a large number, say, 100MB, and then restart the machine (under the Special menu) so it will take effect. It is also a good idea to tell the Mathematica kernel and front end to start out with a fair bit of memory. In the Mathematica folder, click (just once) on the Mathematica icon, pull down the File menu, select the "Get Info" entry, and in the window that pops up, set the preferred memory size to 10000K. Do the same for the Mathematica Kernel, but set its preferred memory size to 15000K.
To prepare homework for submission you will need three floppy disks, 3.5 inch, 1.44 MB, high density. These disks can be formatted by inserting them into the disk drive. In Mathematica, make a new notebook with the New command under the File menu. Select a homework problem from its notebook by dragging the mouse across the cells involved, use the Copy command from the Edit menu to copy it to the clipboard, click at the end of your new notebook, and use the Paste command from the Edit menu to paste it in. Work the problems, saving frequently to the hard disk or desktop of the computer. Do not save directly from Mathematica to the floppy drive, as a bug that may corrupt your notebook has been reportedly associated with doing that. Every 15 minutes or so, save your notebook, then enter the finder (application selector icon in the upper right hand corner), and drag your notebook onto your floppy drive -- it should get copied to the floppy. Each time you do this, use then next of your three floppies, so you have multiple copies of your homework saved. When you leave the lab, put the copy of your homework that was on the desktop into the trash. The next time you come into the lab, put the floppy in, double click on the floppy icon to open it, and use the finder to drag your notebook onto the hard disk icon in the upper right hand corner of the desktop. It should get copied rather than moved -- you can tell because a copy will remain in the floppy, and a copy status window will appear during the copy operation. Work with the version on the hard disk, just as before.
In order to turn in your homework, ensure that your homework notebook has a name which starts with your last name, all lowercase, then a period, then additional identifying information. For example, John Doe might name his first homework notebook "doe.1.01". Then start up Netscape Navigator (under Recent Applications in the colorful apple menu, or in the Network Services folder inside the MAC_APPS folder), open http://cm.math.uiuc.edu/handin, and follow the directions there. You will log in to the system using user names and passwords told to you in class. After that the hand-in procedure is straightforward, and you will also learn how to retrieve your homework.
Let me know if there are any problems.