To start, I lift the foot, grab a scrap and place it under the foot toward the back.
Then butt the first piece you want to sew right against it, so your first stitches will land on the square.
Start sewing and before your needle clears that square, grab your next set of squares, and park it against the first.
You'll have a chain going in no time.
Once all the squares are sewn, flip the last piece, pull the whole chain into your lap, grab your scrap to place under the back of the foot again, and begin down the other side of the center of the squares.
This time will be easier, because the chain has them fairly closer together, and they'll be easier to line up.
When done, snip all the threads to seperate your square pairs.