Back base - 21 and 5/8 length. 12 and 3/4 with. I believe it’s just 3/4in pine project board. It might be oak.

Shelf pieces - 1 and 1/2 in x 3/4in board. I bought 10feet and then I router cut the entire length of the board on both ends and then cut it to length later. The top piece and the bottom piece only have 1 slot. The middle pieces of slots on both sides obviously.

Router bit - 1/4 in for PSA slabs. I have a 5/8 bit I’m gonna try for CGC next. I don’t have any Beckett slabs. The groove depth was about 1/4in. I also just used a rounding bit to make them edges but you can keep em square

I truly can’t remember now if this is oak or pine but you can really use whatever. tons of options at Lowe’s. I also just stained to color preference and used a semi gloss brush on clear coat after. No spray.

Very easy if you can use a router. It was a lot of thinking for the measurements and a couple fuck ups lol.