I installed mupen64plus from the repositories using Synaptic. I like the emulator (for the most part, a couple of graphics glitches on TLOZ Ocarina of Time), especially its performance on my old machine, but I cannot figure out how to configure the controls for myself. I tried looking at Google Code's guide here but I can't find the file I need to edit and the link with the key ids isn't working, so even if I could find the file I wouldn't be able to change anything. So what I need is a resource with the key ids and where to find the file I need to edit.

I am running Ubuntu 12.10 32-bit.
2GB RAM,
Intel CORE 2 DUO @ 2.00GHz

Here's an additional part of the question. M64py is a popular option. However, it requires that you input the paths to the various files it needs. Where are the default locations? Include for both the 32 bit system and a 64 bit system. (The files needed are Library file, Plugin directory and Data directory.)