Here is how I did mine.
Side bars:
were a 2x6, (width of my jointer) Ran them through the jointer for a clean edge and get the width I wanted
that I cut 2x the length/ height I wanted (safer than doing small blocks)
ran them partially through the jointer both sides for the bottom round out (used a stop on the jointer table).
Cut the blocks in half to correct height ?chop saw
Cut dato?s in tops and bottoms-
Sliced them to final dimensions with the table saw with a sled and piece of wood under the cut out portion from the jointer.
Stacked and taped them and drilled holes, maybe should have done this before slicing them but did not have a drill bit long enough and I only have a bench drill press.
Bottom bars:
Stock is going to be the thickness of the bottom bar and the wider the better.
Chop saw to length
Set the full kirf blade (or dato) for the center grove and increment them through with your box jig to correct depth (picture a ? stock with a bunch of cuts through it) Do not forget to include the kirf of the blade for when you cut them apart! (you can see I missed that on the increment
Raise the blade, and split them.
Using the dato cut the shoulder on each side.
Top bars:
Again, full length, cut dato?s for the frame width both ends
Set dato to angle and pushed it again
Cut the kirf for the foundation on the bottom.
Ripped the top bars to width
Cut the wedge out.
Put on a dato and cut the sides dato sides and bottom.