Pattern question for stuffed elephant

I am trying to knit a stuffed elephant for my first niece/nephew. I am pretty new knitter, so I’m having a hard time with a certain part of the pattern. It reads:

Row 1 knit
Row 2 purl
Row 3 K1, M1, K1. 3 sta.
Beg with P row, work 3 rows in st st
Next row K1, M1, K2. 4 sts
Beg with P row, work 5 rows in st st
Next row K1, M1, K to last st, M1, K1. 6 sts
Inc as set on 3 foll 6th rows. 12 sts.
Beg with P row, work 3 rows in st st

I’ve made it to the “Inc as set on 3 foll 6th rows” and that’s where I get stick. I’m not sure what that means. Can anyone help, please.

Thanks!

Welcome to KH!
The increase row that’s given:
“Next row K1, M1, K to last st, M1, K1. 6 sts” tells you where to place the increases, one stitch in from the edges on each side.
If you call that row, row 1 then you would increase on rows 7, 13 and 19.
That’ll bring you to 12sts.
Sounds like a wonderful gift for the new baby.