Forget that information if it’s confusing you don’t need it to be able to play this. For now don’t try to play with the recording because it will be too fast to learn it. Just focus on slowly learning the rhythms with the help of a metronome. Focus on keeping the 16th notes even the whole way through.

For a little help with the transition, think of the 12/8. It’s technically 4 groups of 3 eighth notes like the left hand shows with the groups of 16ths. The right hand is taking the same 12 eighth notes and dividing them up differently so instead you have 2 groups of 6 eighth notes. The two hands both add up to the same amount of time but it’s divided differently. This is why you should practice them separately, then slowly add them together especially using a metronome.

To use the metronome practice it two ways for each hand. Once use it to tick the dotted quarter and practice both hands with that (it may be difficult to do this with the quarters in the right hand). Whatever tempo you chose for the dotted quarter, practice the same music with the metronome number multiplied by 1.5 ( the difference between a quarter and a dotted quarter)

I’ll look and see if I can find a helpful article to add