If you were able to do section #2, section #3 should be easy for you. It is a variation of the Satin Stitch, just now creating texture and a different shape.
*Remember for the diagrams below, each line represents a thread of your fabric, and all stitching is done using 2 threads.*
Bring needle up through 1 down through 2 then up through 1 and down through 3. Move one thread down and repeat the same and continue doing this until you reach the bottom. Flip the diagram upside down to create the upwards stitch.