Turtle paludarium problem

I have a southern painted turtle and I am currently planning on creating a paludarium for him. I want to have some ledges in the tank in which I could put soil in and grow plants and also to let him bask, but I don't know what material to use to create those ledges, let alone let them stick on the walls.

Also, please provide some plants for the paludarium, it's my first time building one! (must be turtle safe)

thank you