Step 1: Basic shape and cutting the rabbets
I used a belt sander to shape the basic profile. Working with the grain of the walnut, which runs along the prongs for strength, I shaped the profile you can see.
Then I used the table saw to cut the rabbets. This was tricky and I messed it up a few times. I ran the piece through on end with the saw very close to the fence. The problem I faced was that the cutout for the saw blade was too big and the piece wanted to fall down. That made the cut inaccurate as I was basically free handing it. Next time I'd use a sacrificial board with the blade raised through it but I couldn't see a way to fix that down at Techshop, where I was working.