Is there a place that lists and EXPLAINS xterm general commands?

I downloaded mplayer but cannot find it. Application manager did not ask me what folder I wanted to put it in.

I am also a newbie trying to use xterm, root the 770.

Also, after rooting and increasing the memory, what else should be done to this thing.

xterm, is like the command prompt of window, it runs a shell for the os. The 770 is running std linux commands whereas the windows command prompt is basically dos.

Find a linux tutorial and you will learn the majority of what can be accessed thru xterm (x - terminal)

Hope this helps you find your answer