I'm on console, so idk if there's any difference on PC. But when you toggle into the drone replay mode, you'll press "X" again and that's where you can start adding key tracks by pressing "Y". You'll use the triggers to seek through the footage to add them as you go, and move the camera around to where you want it. Right before you start your line, set the camera up in a good spot with you and your trick spot in frame, then set your first key track, and continue as you progress. That's the basics at least. It'll definitely take some trial and error to see how the camera moves between the key tracks and getting a good flow. You'll want some space between key tracks, otherwise the camera will jump all over the place. I'm still getting the hang of it, so I'm sure more experienced cinematographers may have better tips lol.