Cabana

I am sorry I don't usually have set plans when I build but hopefully I can help you somewhat. I used double walled PVC for the cabana but I think I would try 1 inch single walled. You can get the corner pieces on-line (they were not available locally). I made it the uprights 6 foot high, wide and deep. I put 45 degree corner pieces to prevent scissoring. I just had to do trial and error since I didn't remember solid geometry.
The corner pieces are three-way, a right angle and and one going up at the corner. These are used for the base.

http://pvcfittings.com/

These are used for the top along with a 45 degree connector (turn so straight portion is vertical).
Putting these at the corners prevented it from scissoring and collapsing i.e. scissoring is when the square collapses and becomes more like a diamond.

I have seen cabana's online at WalMart and they were about $100. By the time you get all the supplies this ends up about the same.
The chairs are easy. I just copied a picture from the internet. Just remember to keep the parallel sides the same length. It helps to clean the pipe and then glue them. We glued the left side together and the right side together and the cross pieces. We then put the sewed seat on and screwed the left and right sides together by placing a tiny screw underneath the bars. The seat is a heavy cotton that I doubled. I prewashed it to make it shrink. That way we could wash it again. They lasted through a year with kindergarten class and we still have them.