I’m posting this edging pattern separately so that it will be easy to find , if you want to use it some time.
So this is what I did.
Start in one of the sc in the previous row,
Ch 3, 1 dc, *(Ch 4, Sl st in the 3rd ch from hook, Ch 3, Sl st in 3rd ch from hook , Ch 3,Sl st in 3rd Ch from hook, Ch 1, 2dc.)* then
2 dc, repeat from * to *. Finish off.