the row where I think it all went crazy was here
Inc row (RS) K20, place marker, M1K, K2, M1K, place marker, K20, 44sts,
continue to inc 1 st after first marker and before 2n marker, every RS row 4 times more, end on WS, 52 sts, 12 sts between markers, (i got this) looks good and then
Shape thumb opening next row rs K20, drop marker, bind off 12 sts, drop marker, K20
I did not end up with an opening! :/
following row, P20, cast on 2 sts, p20, 42 sts,.
rib, bind off
When you bind off the stitches between the markers and then knit to the end of the row, you should end up with a gap just as you would when you knit a sweater and bind off the center sts at the neck. You would have 20sts, the gap with 12sts bound off and then 20sts on the needle. On the return purl row, you're filling in the gap with 2 cast on sts and then purling 20sts so that starts to give you the shape of the thumb opening.