this row is going to be different: we are going to make sets: 2 sets of 3dc's and 1 set of 3 dc's. as you see in the picture above. after your chain 3: make another 2dc, chain 1 and then 3dc's. chain 1 and move onto the next chain1-open space and make another set of 3dc. but NOT two sets. this row is: 1 set, 2 sets, 1 set, 2 sets (separated by a chain 1) all around.
10x 3dc's. so the first row (yellow) has 5 sets of 3dc's. the next row (orange) has 2 sets of 3dc's in each open chain-1-space: so 10 sets of 3dc's. i hope that make sense. otherwise grab yourself some coffee and come back later. now join in the second dc of the first set of 3dc's (see my picture above). chain3