Here's a good explanation of how the "multicam" approach works in terms of editing.
Note that she's recording one take onto multiple cameras. that's one way of doing it.
Another way is to record multiple takes on one camera (e.g., separate video for each of your audio tracks that you want to record). In this video, change "Camera 1", "Camera 2" etc for "Track 1 (Bass)", "Track 2 (Guitar), etc. and the principles are identical.
In either approach, you need to ensure you capture your audio in your DAW AND onto your camera (for syncing purposes in the editing software). You'll dump the camera audio for the final edit and use your DAW mix.
Basically, you record and mix all audio in your DAW. Then edit video with the DAW audio in video editing software.
Assuming you record each audio track into the DAW and record onto video at the same time, here's the overall workflow for a one camera/multiple video clips process:
- First, export a final mix from DAW and import into the video editing software.
- Import all your video clips (incl. camera audio) into the video editing software
- Then sync your video (with rough audio) to the DAW audio within the video editing software (you may need to reference the YouTube video below to figure out how to do that).
- Then get rid of the camera audio after syncing all video clops to the DAW audio mix (either by deleting the audio track from each camera clip or by zeroing out the audio from each camera clip).
- Then start editing* the video clips into one complete video synced to the DAW audio.
- Finally, export the complete video/DAW audio sequence and upload to Youtube.
*this is where it starts getting technically challenging, but editing multi camera sequences in package like Premiere or Resolve is quite easy once you get the hang of it. Learning curve, YMMV.