Start with a printout of the various units that make up the block, this will be the foundation of the block
start stitching the units together, making sure to stitch on the lines, the faint dotted lines are the seam allowance
a completed unit C
the completed units that make up the block
the completed units ready for stitching together
the wrong side of the completed block
and the completed block
The foundation paper gets gently ripped away later on.