This is probably the best place to start with anything computer-wize - how to write a list. The ls command lists the files in the current directory. 

Stage 1: open up a terminal

Stage 2: type     ls

Stage 3: press return (This is really as easy as things get around here)

Stage 4: watch as pretty lists appear as if by magic (unless you are in an empty directory when you will be disappointed)

Useful added extra options:

ls -a lists all, ie includes hidden files

ls -l lists extra lists ie it tells you about the file

ls -F shows the type of file with a \ for a directory, * for an executabe file, @ for a symbloic link (I have no idea what that is, but I can now identify it in a list)

ls -alF tells you everything (but I wont understand it)