You record the audio on your camera as well as with the H6 recorder. Most good video editing software lets you then synchronize the audio from the video with a separate audio track automatically. If you're using Final Cut Pro, import your video and audio file, select the video and matching audio file, then press Option+Command+G to synchronize the audio. It'll create a synchronized video clip that uses the audio from your recorder instead. You just drag that clip to your timeline and edit that instead of the original video clip. Adobe Premiere and DaVinci have similar functions.
Hi @Plug&Play as far as I remember, all I did was a "Auto-Match" the Loudness of the audio track in Premiere Pro so that you could hear what it sounds like straight out of recorder. I normally also add the "Balanced Male Voice" plugin in the Audio Panel in Premiere Pro when I use this recorder for all of my voiceovers and talking head RU-vid Videos. If you have any other questions please let me know.