Larry, I have a copy of the PCIS manual. No I am not going to give it away. However, I will help you.
When you open PCIS you will get a screen that has several function keys listed. Use F1 to load/save your file. A working knowledge of DOS will be helpful here to change to the proper directory.
Use F2 to get into the editor.
To add documentation to a contact in the program, after you enter the contact address you enter letters for the label. So if you have entered
001
-----] [-----
And you want to label it PB_1 then you type the characters 001PB_1. Press enter to accept.
To enter a rung comment, place the cursor on the rung you wish to comment and press F7. The cursor will move to the right of your rung number and you can enter the rung comment. Press Enter to accept.
At the bottom of your screen the valid function keys for what you are doing are displayed. As you navigate around the screen these keys will change. Pay attention to them. For example, when you are on a rung the F7 key changes to allow you to use it to enter a rung comment.
Several people have already linked the SLC100 manual available from the Rockwell Automation online literature library. I suggest you click on the link and open the manual. While it does not cover PCIS per se, having a working understanding of the SLC100 will make the functions in PCIS obvious. PCIS is a bare bones ladder editor. Don't look for too many bells and whistles.