Here are the two cabinets that will have the lighting I mentioned in part 1.
I'm also making shelves that will go above a different cabinet, These will be 3" thick with a flush top and bottom. I start by cutting the tongues on the fronts of the shelves.
No fancy measuring tools needed, just mark a few lines and double check with a tape.
Next cutting the groves for the tongue. Make a test piece, double check with tape.
When happy with the fit cut both edges, top and bottom.
Measure the inside, between the grooves, and make a frame to fit in between, Then glue and clamp the front on , cut to length when it's dry.
Thanks
Figuring out how to do something you have never done is what makes a good challenge.