I'd add too.
You will need a lot of filming (shooting). So prepare your digital camera, even iPhone will be OK.
The main thing is a concept of video. So write down a simple scenario. Even if it doesn't include performance by other artists, just performance of your son, still write down the beginning, the main part and ending scenarios.
Based on scenario, prepare the shooting stage (room, street, location), etc.
Prepare additional lighting if necessary.
Shoot actual video, usually by 1-2 cameras.
Prepare to shoot in different takes in different locations, if necessary.
You will need to sync the video so use something to make loud noise at start of shooting (like this
, forgot its name, but its not necessary, you can use whatever you like.
Once you shot your videos, download them all,
Start to edit using a video editor (I would recommend iMovie, you can use whatever you want).
Make an actual video using the music track as a base, add video, transitions, effect based on scenario.
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