Most of the videos are very long and multiple part videos. The plug is the first step. You make the mould from the plug.
This one is very short, but gives you the idea.
https://www.youtube.com/watch?v=gOBGKSveCGcYou don’t necessarily need to start with nothing and build a wood boat to make a plug.
You can use an existing hull. You can cut it up, reshape it, shorten it, make it longer, change the design, add different features etc.
Sometimes you can copy a feature off another hull and incorporate that feature into your design.
Example: you want to have a center pod to make your tunnel a Mod VP. You see a center pod on another hull you think would work. You could make a mould of that center pod and use it in your design.
The plug doesn’t need to look pretty. It can be a match work on many pieces. Your only concern is the outer skin. That is the surface the mould reproduces.