You definitely don't need to know buckets and buckets of theory to be a good player. It helps, but even the most knowlegdable theorist shouldn't think to much when playing. To apply pentatonics to playing over a jam tracks, here's the order you should know.

1. What key the Jam track is in. (i.e. E major, A minor.)
2. What are the chords in the jam tracks. (you should start off with 3-4 chord vamps).
3. Match the pentatonic scales with each chord.
Major pent over a major chord.
Minor pent over a minor chord.
Match of chord and pent.


example chord progression.
||: Gmaj // Em // Cmaj7 // D7 :||
G maj pent // E min pent // C maj pent // D maj pent


Now just play and that's it.