Kennel roof

I just got a 10x15 kennel..the retriever from tractor supply..I want to put a corrugated roof on it. It is powder coated steel. The frame is 1.26". I was thinking of running 2x4 parallel To each other on opposite sides, connecting them by drilling hole through top frame and nut/bolt through 2x4. Then using joist hangers on those to run some across between them..then fasten the sheet metal to those..and some how add a slight pitch to it..any recommendations for this project??
.

Just a thought
Nail a 2x6 to the 2x4 making a "L" fasten the 2x4 to the 15' top rail
Fasten 2x4 to the other side flat
Install 2x4's on 2 ft centers on short span
Nail 1x4's on top of 2x4 joist at 16 or 24 centers for metal to secure to

I welded some 2x4 purlins across the top and screwed some r panel to that. Very little pitch, rain still runs off the downhill end. It was 2 5x10 kennels and I expanded it later with 2 more slots. Just added on to the roof with matching r panel.