your first round had a series of Ch1 places which are called ch1-sp or chain 1 space.
Row 2 Ch 3 – counts as dc, Chain 3
5 dc first in ch-space, Do 5 double crochet in the first space of the row below.
*sc in next ch-1 space, 6 dc in next ch-1 space – shell st made
; repeat from *, do a single in next chain 1 space, then do 6 double crochet in the following ch1 space; repeat this (sc then 6 dc) almost to the end
ending 6 dc in last ch-1 space – 6 (16, 25) shells. In the last chain 1 space , do 6 double crochet
Fasten off, leaving long tail for anchoring Rosette.