First, you have to gather your supplies. You'll need
8 cedar boards 1x4x16in (six with curve cuts if you want for the seat) 8 cedar boards 1x4x47in 4 cedar posts 4x417in 56 2-in deck screws 32 1 1/4-in deck screws (for seat slats) and 1 qt. exterior oil finish if desired
I bought 6 -- 1x4x8' cedar boards and 1 -- 4x4x8' cedar post and had plenty of wood for the project, seen in the picture.