I use this page for reference when talking on the phone
Machined corners to compensate for the radius of the cutters.
Using these methods will give you perfect precision.
The lefthand joint looks like it has a three quarter circle on the corner this is not the case, All you need to do is put a circle on the corners idealy on a seperate layer.
We drill the holes with same tool that we use to cut the profiles.
Tagging is a very useful way to machine panels without elaborate jigging.
It's a good way to transport delicate parts.
A Plywood fretted panel with a tags left and right.