What I've found as the easiest way to go about it is to first make up a pattern that has all the required elements for that level. Next, video tape yourself doing the pattern as you would at the show (no schooling mid pattern, no added bits, etc.). Next, since training level is mostly trot, find music that you like and fits your horses trot. It's recommended to have music without, or very minimal lyrics as it can be distracting. Once you have your trot music, find walk and canter music that fit your horses movements, but are also the same genre, or complement your trot music. From there you can compile your music together to fit your pattern. Then it's just a matter of learning your music and practising your pattern to it.