Look in a printed manual for general help if you can. You should have someone show you some things and then read "Using and Managing AIX" manual.
The commands:
man -k keyword lists commands relevant to a keyword
man command prints out the manual pages for a command
are helpful; other basic commands are:
cat - concatenates files (and just prints them out)
ex - text editor
ls - lists contents of directory
mail - sends and receives mail
passwd - changes login password
sccshelp - views information on the Source Code Control System
smit - system management interface tool
tset - sets terminal modes
who - who is on the system
write - writes to another user
You could find programs about mail by the command: man -k mail
and print out the man command documentation via: man mail
You can log out by typing "exit".