Fix the first board at the start of the fence line with the top of the board flush with the top of the middle rail (The bottom of the board should be 50mm (2″) from ground). Use a plumb level to ensure the board is plumb (vertical) and nail in place using 60mm (2 1/4″)...
The lattice frame usually consists of uprights (posts) and top and bottom plates. The uprights, in a lot of cases are posts either concreted into the ground or bolted to another structure such as a deck or retaining wall. An upright may be a post for a fence, a pergola, an arbor, ...