Hi there ! Question about a “set up”row

Pattern reads row **row 3 knit
Row 4 ( set up)k10 Pm p10 Pm k40 Pm p65 Pm
K10
Row 5 knit slipping markers as they come
Row 6 [ knit to marker, Sm, purl to marker, Sm]
Twice, knit to end

Knit 5 & 6 for 40 times for total of 80 rows
Can’t figure out this establishes a offset garter stitch in the pattern but I’m stumped !

What is the name of your pattern?
There’s going to be alternating bands of garter stitch and stockinette.

Tincanknits maltblanket

Oh, very nice!
https://www.ravelry.com/patterns/library/malt-2

The pattern suggestion about markers is a very good idea. It’ll help maintain the garter stitch square for the 80rows of this part of the pattern.