Riveting is the technique that allows you to assemble your hull with enough flexibility for it to assume its natural shape. Each rivet connection is made up of two plastic cable ties. Once you have found a matching set of stitch holes in a pair of planks, the first cable tie is inserted through the holes from the inside of the hull, passing through both holes.
From the outside of the hull, the head of a second tie is slipped over the tail of the first tie, making the rivet assembly and locking the planks together.
Stitching is used wherever the tail of a cable tie can be brought back through it's own locking head, creating a loop. In your hull it will be used to connect the two hull halves together along the keel line, where the tail can return to the inside of the hull through the matching hole in the other hull half. This is the way that a cable tie is normally used.