Continue adding blocks untill your row is complete. Once all your blocks are joined into rows, you are ready to join the rows together. You use the same method with the backing strip under the row and the folded strip on top.
At this point I do pin together. Place a pin where the joining strips are matched to the other rows strip. I also put a pin between the joining strips. Be sure to check the placement of your blocks as you go and make sure your blocks match correctly before you add a whole row to the others.
When you finish your quilt can look something like this one.