Red eared slider basking area idea?

I have a red eared slider and I'm making a custom basking area for him. It's going to be one that sits on top of the tank with walls on the outside edges and open where he can jump in the water. The ramp is going to be at the very back of the tank, somewhat centered across the back pane. What I'm having problems with is trying to figure out what I should use as a surface where they will bask and if I should put any decorations in the area and what kind. I also want to fit in an area for my female to lay her eggs. I was thinking of putting in a removable wall that just has a bunch of soil on the other side that I will make available when she is ready to lay her eggs. Please respond, and thank you in advance.