@mcsteve

Assuming your controller has enough buttons to support all of the N64 buttons, all of those buttons are available by default if you configured all of the buttons on your controller during the initial gamepad detection. If you need to reconfigure it I recommend resetting your controller configuration in the Retropie system menu->Retropie Setup so that it prompts you again.

how do i make it full screen? my tv is 4:3 640x480 and i see two black bars one on top and one on botton! i want to stretch it

@courtesybear howchoo =death by ads.

Official docs are ad free ;)

@ironj679 Look in /boot/config.txtChange your overscan setting from 1 to 0 or the other way around. This just depends on your monitor.
If it still off there are 4 individual overscan settings for each side of the screen. Have a play about with these. Remove the # before to activate. After any change you will need to reboot to invoke the changes made.