How to record and replay a chop

I was wondering if it were possible to record certain beats of a playing song using midi and have these converted to chops to affect op parameters.

Once you get the MIDI into TD, you can use the Record CHOP to record any CHOP input over time.

Playback is then achieved by using a Lookup CHOP and driving an index into this Record CHOP’s data.

drive it how? I’m not connecting the dots on this yet

Please take a look at the OP Snippets examples for the Lookup CHOP, it shows a number of ways to use the Lookup by driving the index, examples lookup and lookup1 are the most basic versions of what you need.