Stuck on socks!

[Stephanie Wood]

Hi ladies!   
 

I feel like an idiot- I’m completely stuck on round three of this pattern.   I just can’t seem to figure out what it means.   I’ve included a photo of the full pattern as well as round 3.   
 

Thank you for any help you provide!! 
Stephanie 

Edited December 22, 2019 by Stephanie Wood

[Granny Square]

Pattern link   (a little easier to read, and we don't want to get this site's owners in trouble for a copyright violation)  It's OK to post a line or 2, but not a scan of the whole thing.  So here's line 3:

3rd rnd: Ch 1. 1 sc in same sp as last sl st. (1 sc in each sc to next marked sc. 3 sc in marked sc) twice. 1 sc in each sc to end of rnd. Join with sl st to first sc. 20 (20-26- 26-28) sc.

Round 2 stitch count was 16 (16-22-22-24) sc.

Look at the stitch count at the end of round 2, and at the end of round 3 -- all of the sizes increase by 4.

"Twice' struck me as the thing that might be a point of confusion.  There are a few ways to make socks, but the shaping of the toe differs mostly on whether it's toe-up or toe-down, and the increase scheme is pretty much the same.  On each side of the foot, usually evenly spaced apart, you mark a point, like your pattern does.  Then (for toe up) you increase before and after that mark on 1 side of the foot, and again at the other mark at the other side of the foot, and continue in the same way for a number of rounds. 

By marking a stitch, and then in the next row putting 3 stitches in that stitch, you've created 3 stitches where there had been 1 - the new middle stitch is the new 'mark' --so each side of the sock increases by 2, times 2 sides of the foot, which makes an increase of 4 stitches for each round of the toe.