I make my instruments in the Spanish method where the sides are let into two deep grooves cut into the neck. This is the way classic Spanish guitars have been built for centuries.
the grooves are cut on the bandsaw. the neck will be glued to the soundboard so the grooves line up with the pencil mark denoting the position of the side.
The indent which is glued onto the soundboard is cut out by numerous cuts when held in the sled.
Here you an see that it is partially cut. This indent must be the exact thickness of the soundboard. Set your saw blade carefully.
And now the fun part, Carving the "hook" and the neck.