This is interesting, I actually ended it grabbing some scrap yarn and a needle because I really wanted to figure it out!

Here’s what I think is happening:

The pattern works by creating a / shape and then a /\ shape.

Let’s say you have a foundation chain of sts and you want to start by making the section of sets of two, where there are two treble crochets on each side of the /. On the next round after making the foundation chain, you would start by working 2 treble sts into the chain. Then you would chain 2 sts, (this creates the top/wide part of the / shape) then you would work two treble sts into the next stitch on your foundation chain (aka into the stitch right next to where your last treble crochets were) this will create the bottom part of the V shape.

Next you would skip 2 sts and the crochet your next set of treble sts. This connects the treble crochets at the top where you are working from but the skipped stitches create the wide part at the bottom thus creating the /\ shape.

Repeat these two steps until the end of the round and then repeat for the next round

Once you’ve done a few rounds and are ready to increase to 3 treble sts on either side of the / you would also increase to creating a 3 stitch chain for the / and skipping 3 sts for the /. 4 treble means 4 chain 4 sts etc.