Excellent advice given here already. I only recently got my Mavic but had a lot of R/C fixed wing (giant scale) experience. Also performed LOS takeoffs/landings for fixed-wing drones (in coordination with FPV pilots). That experience, while a plus, didn't help all that much when it came to the Mavic.
I would recommend reading as much as you can regarding the dji Go 4 app, and its settings. By "its settings" I really mean the Mavic's settings as the dji Go 4 app is how you will configure your MPP. I would focus more on flight settings in the beginning more than camera settings. Screw up camera settings and you may get a bad picture. Screw up flight settings and you may never see your Mavic again.
Of all the functions to understand inside-and-out, I would say Return to Home (RTH) should be the first priority. Many lost/crashed reports I have read seem to include a failure to fully understand RTH. This could be anything from landing in water, crashing into a ceiling, or not being able to make it home in wind.
Mike