The idea of these things was that you signed in and were presented with what you needed normally via a menu, you selected the menu option via its number and behind the scenes the program/application was run. The user couldn't just install what they wanted.
To run a prgram and assuming you have a command line? Type RUN PGM and prompt it with the F4 button.
Something I should have mentioned is that RETURN and ENTER are different, ENTER is normally where the right CTRL is on a PC keyboard, RETURN is the carriage return on a PC keyboard.
The way to proceed now, sign in as QSECOFR and on the command line, type in WRKUSRPRF *ALL, this will list all of the users on the system, it may take a while to list them, but when it does, choose one and take a look, think its 2 to modify it and you should be able to change the password from there, sign out of QSECOFR and then sign in with your newly changed profile, you'll see what I mean. Don't choose something that begins qith a Q though, leave those alone for now.
Version number should be displayed on the console when you sign in.
I recall going on a 3 day course to learn basic operations as it is so different.
S