Okay. I was asking cause my buddy showed me how he edited some video he took while boating at the lake, but he was using the DJI app on his phone. I don't have editing software or anything so I was just going to use the DJI app to do it.To clarify, the DJI system allows (configure in DJI Go4) the recording of two versions of the video file simultaneously, one directly to the SD card (high quality) in the drone and one cached version that is transmitted to the CS or phone and recorded on it's internal memory (low quality and subject to transmission interference). The cached version on the CS is more for emergency record keeping rather than formal use, it allows for a quick preview/review and reshoot if necessary. It's also a record of the flight if you end up loosing the drone and the SD card on it. You can transfer and store the cached version on the CS SD card but this is a bit superflous if you already have the drone SD card high-quality version. The main thing is to have the SD card in the drone to record the high quality files and don't rely on the CS cached versions.
For editing it would be recommended to use the high quality version of the video from the SD card in the drone, downloading it most probably onto a PC or laptop. I've not heard of anyone doing full scale editing on a CS as you need a lot of processing power and ram memory to do this well and the CS does not have this performance. It's better to use dedicated video editing software like the free Davinic Resolve (there is a free version DaVinci Resolve 16 | Blackmagic Design) instead of using DJI Go4 on the CS to do it.