add link to CP menu and display 3rd party data

I'm new to modx but pretty comfortable with php. What I need to do is add a link to the end of the CP menu(after Support) and on the page it links to I'll need to display info from a 3rd party thru their API(I should be fine on this, I just need help with the modx integration). I'm not familiar at all with modx addons but what I've read so far has me lost and confused. Can someone confirm that what I'm trying to do is possible and point me in the right direction? I've only found info on editing the menu on the front-end. Is there a common structure for addons that I can start with and maybe point me to the hooks I would use?

Thanks,
Gary

basically you would do this:

http://rtfm.modx.com/display/revolution20/Custom+Manager+Pages+Tutorial

Great. Thanks for the help Bruno.