Don is correct. The 2 methods typically used is T & G or lap. There are 2 types of lap joints. In one the boards are tapered, thin at the top and thick at the bottom, and the other is the shiplap style joint (easiest to do) where the edges of both boards are rabbetted, one on a face and the other on the back side. A jointer works great for making a lot of rabbets in a short time.
A 3rd style is vertical with about 4" between boards and then another board placed over the gap (board and batten). No matter which method you use you will need at least 2 more rows than you thought.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.