Good luck. I'm a newbie too with only a couple flights logged, both successful. My advice, 1) download the manual and read it thoroughly, 2) make sure your avoidance sensors are on and RTH height is several meters higher than any obstacle in the area and ascend straight up to at least 30' to establish your precise home point before giving any pitch input , 3) Take your first flight in beginner mode for 5-10 minutes and let it hover at times to study your controller and phone/tablet displays.
If all goes well and you're comfortable you might land, switch off beginner mode and take it up a little higher and farther out for another 5 minutes or so and test RTH. If it's in sight and something goes wrong you can always cancel RTH and fly back manually. Remember you can always let go of the sticks and the mavic will hover in place while you figure things out if you're not in RTH mode. Make sure your battery warning level is sufficient- 30%?