We start by jointing, crosscuting, ripping, and planing the pieces to final dimensions
And we end up with a few stacks of wood - we label each stack, otherwise, we'll lose track. There's quite a few little pieces - some with very similar, but different dimensions. I've learned the hard way to keep track of the pieces for this kind of project. Sometimes, I put a piece of tape on the piece and write it's name on it. On other projects, I might just write something in an inconspicuous spot, like on a tenon. In this case, I keep the stacks separated and put a tag on each stack.
Those pantorouter/slot mortiser joints are so nice and fast to make. All of these joints are 1/4" x 3/4" which makes set up a breeze.
We first glued up the sides, let it sit for an hour or so, then glued up the rails