The one thing I highly recommend is making sure that the posts and floor is level. We would attach and then check to be sure everything was still level. Then repeat. I'm sorry that I don't have pictures of the process. We get so caught up in our projects that we forget to stop and take picture.
The structure is very simple and hopefully you can see the details in the finished product.
Materials used - Exact amount will depend on your shower size
4x4 treated posts
1x6 treated planks
2x4 treated boards
concrete deck blocks (click for link)
galvanized tin custom cut for the project
screws (both wood and metal)
drill bit for pilot holes