First of all, you should make sure you already know how to patch in Puredata, or are willing to learn. Do this by downloading Miller Puckette's software from here. Then read through the HTML documentation to learn how to use it. There are also some good resources at the Puredata portal. Finally, the best resource of all is the vibrant community that you can join by signing up to the pd-list.

If you already know how to make puredata patches, there are a few considerations you need to take into account when making patches for gp2xPd:

• PDa is a fairly limited version of Puredata which uses fixed point math instead of floating point math internally. You can read more about that at the PDa homepage. The main issue with that seems to be the way in which arrays are accessed - by millisecond rather than sample index.
• The Pd file parser in gp2xPd is very stupid. A single 320x240 screen of GUI objects will be rendered. If you have gui objects in subpatches it won't know they're in subpatches and will still try to render them. If you put objects outside 320x240 they won't be rendered. Just put a few GUI objects in a 320x240 area at the top level of your patch.
• Currently only 3 types of things are rendered by gp2xPd:
  • comments
  • number boxes
  • toggles
• If you give the gui elements fancy things like colours or sizes or font sizes or anything like that, they will be ignored.
• For some reason the [mtof~] object will slow your patches right down to a crawl. Use the [mtof] object instead, which only acts at control rate.
• Once you've made a patch that you like, you need to create a .gpe file to launch it.

Probably the best way to get started is to make a copy of the bigtest.gpe and bigtest.pd files. Change the bigtest.gpe file's launch command to launch the newly named Pd file. Load up bigtest.pd in Puredata or in PDa running on your PC and modify it to your taste. It's probably best to use PDa compiled on the PC as that is the closest thing to your actual live environment. Now create some wicked gp2x controlled sound machines.