The 700 series machines (720s and 700RX terminals) default into HP Vue when you login to the system. You can use the various facilities in the windowing manager to customize your environment. You can also edit certain files to customize menus and the like. More detailed information can be obtained from the man page on "vuewm" or "vuesession." You may also want to poke around in the .vue directory that gets created under your home directory.
Some people are more familar with Motif Windowing Manager (mwm). Also, some applications will not run properly under HP-Vue and require Motif Windowing Manager. See "helpme xwindows-mwm" for information on using mwm instead of HP Vue.
More information about how to use X Windows can be found in "helpme xwindows-apps".
Information about the X Windows libraries is available in "helpme xwindows-libs".