WOnder if anyone can help, I just downloaded Retroarch but the interface is totally all over the place.. I can't seem to navigate anywhere properly, some joypad buttons move forward and another exits but largely wth?! I'm running Skelton's custom, any advice?
From a high level, get the latest revision from the retroarch website (google it). Once installed you go to options and to inputs and there is something like "input all" where it will run through every button and you touch the button the GPD that you want to map to that. Once your keys are mapped you update the cores which are the emulators, then point retroarch to the root of where all your roms are (mine are on /mnt/external_SD/SNES,NES,GB,etc). I'd also suggest mapping the RGUI button to R3 Left or R3 Right - this allows you to get to the save/load state screen after you start a game.
For me details check out this setup link -- http://lifehacker.com/how-to-set-up-an-all-in-one-retro-game-emulator-with-re-1745863517
If that one doesn't work for you, google "How to setup Retroarch" and you will get a bunch of videos and links.
After I understood the basics I put up above, retroach became easier to understand. I now use it for emulators I don't want to download like Atari 7800 EMU.
Its good but not quite to the point where I would dump all my individual emulators just yet. I wish they had the Muppen64 AE+ core for Nintendo 64. The one included didnt work for me, but stand alone Muppen works just fine.
Hope this helps