Welcome and congrats on getting the Prophet 12, it's a very fully featured synth. You should find plenty of good tips and tricks in this forum, some of them might need proper time to digest as this synth goes very deep.
One quick tip that really helped with the workflow for me that might save you some time: When assigning modulation for an LFO or ENV, just hold that selector button (1, 2, 3, 4 and ENV 3, 4) and wiggle a knob to assign that mod target. Also, if you want to use the mod matrix assign button, you can holed the "Assign mod source" while pressing the OSC, LFO and ENV selector buttons to quickly select those as mod sources. I very rarely have to manually scroll down the mod matrix list since I realised that.