From my understanding of what you have written here and from working shell pattern stitches in garments, you do not decrease by double decreases.
So you should do 7 shells + 1 dc in next dc (not sure if this dc is part of next shell or not). THEN you turn your work and ch 3. And it looks like row 2 is the same thing, 7 shells + 1 dc in top of ch 3.
Hope that helps!