Mile a minute pattern help!

I'm having trouble understanding the pattern when it comes to the edging. The afghan is worked in rows across instead of oblong. The edging instructions are...
Rnd 1: Ch1, turn; sc in each st and in each ch across to last dc,2 sc in last dc; (have up to here.. this is where i'm stuck) 2 sc in first row, 3 sc in end of each row across; working in free loops of beginning ch, 2 sc in first ch, sc in each ch across to marked ch, 2 sc in marked chain, remove marker; 2 sc in first row, 3 sc in end of each row across, sc in same st as first sc; join with slip st to first sc; 512 sc.
I think once I understand this first round, I'll be able to figure out the rest.
When the pattern mentions a marker... the only marker the pattern called for was on the beginning chain. "Ch24 loosely, place marker in fourth ch from hookk for st placement." If i continue moving down the strip for Rnd 1, the marker is on the opposite side of my work.
Please help... I think i'm making this more difficult than it really is.
Thank you,