Making first project

Hey, just wanted some advice on making my first big gear project. A bivy sac.

I downloaded the plans from Six Moon Designs but I was wondering if there were any other plans for MYO bivys out there. Or wether I should go from scratch and make the whole thing myself.

I was also wondering what materials to use because I would like it to be fairly durable and a few years. Another thing is I'm not sure where to go and buy the materials from so any recommendations would be nice.