Don't know how to explain. Take 2 strips, one on each side of a block and sew all 3 together with the block between the strips. On one of the strips it might work best to iron a small fold (to hand sew it down). Take another block and and sew the unironed strip to another block. Once you have that done you should have 2 blocks joined with a strip and the other side should have only one side sewn down. Now take the ironed strip and fold over to hand stitch closed. After the blocks are joined do the same to join full rows.
I tried to warn you as this is probably clear as mud maybe someone else can explain better than I. Good luck.