Help with “Hermione’s Time-Turner Sweater”

Hello everyone, 

I’m currently knitting a sweater from a Harry Potter knitting book. Unfortunately, I’m not really getting anywhere and hope you can help me. 

In the pattern for the sweater, it is worked from the top down. First, the ribbing at the top is knitted in the round in 2x2 rib, 2.5 cm. That much is clear. After that, short rows start, and this is where my problem is. 

So I have one round with x stitches and a stitch marker at the beginning of my round. Now I’m supposed to do the following:
Row 1 (RS) 
Knit 86 stitches, place SM, k6, turn - that much is clear
Row 2 (WS)
Double stitch, [purl sts to SM, slip SM] 2x, p6, turn - here the 2nd SM is probably my beginning of round again?
Row 3 
DS, [knit sts to SM, slip SM] 2x, turn - here I’m completely lost; I’m back at the beginning and only have one SM, so where exactly should the second SM be here?
Row 4
DS, [purl sts to SM, slip SM] 2x, turn
- I already couldn’t follow the part above

The pattern for the upper part continues through row 7, but I simply don’t understand the procedure with the stitch markers. 

Could you maybe explain it to me? 

That would be really kind of you. 

Thanks in advance. 

Best regards

The markers are really just there to make counting easier for you. You know you can keep following the pattern until you reach the marker, so you don’t have to keep counting stitches. :-)

And slipping the marker is pretty obvious, but we authors still include it just in case—because there’s always someone who knits the markers right into the fabric. :-D

Thank you so much for the quick reply 😊

So I basically have the marker for the start of the round and the second one, which is added in Row 1, and I switch back and forth between the two?

Row 2 (WS)
Double stitch, [purl sts to SM, slip SM] 2x, purl 6 sts, turn - here the 2nd SM is probably my beginning of round again?
I would like to know what the 2x after the bracket means.
Maybe someone can explain that to me or knows of a video about it.
Thanks, best regards

What’s in parentheses is worked twice. That’s all it means.