This is a free sock pattern, and I am no sock-knitting expert, so I was not too surprised to get stuck. But after finally getting the cuff correct on the 4th try, I thought I was home free on this sock, then came the heel flap.
I was following the pattern ok, but it just wasn't looking right. I consulted you-tube on slip stitches to make sure I was doing it right and tried both slipping knit-wise and slipping purl-wise, but it still did not look right. So I un-knit. And tried again. And even tried it with some scrap yarn. Finally I decided I would just go with it even though it didn't look right.
And it turns out it was right, I just wasn't looking at it from the right angle.
Lesson in crafty persistence!