So i have gone through this thread, i understand that this is your first flyer.
I recomend taking this project step by step. Rather than making a prototype in which you can fit you gps module, parachute, and flight controller. Make a simple hand glider, modify its design to see how the flight time changes. It will also help you do and understand good manufacturing.
I RECOMMEND adding a literrature thread in this page so everyone can know what you have read so far about gliders and flight mechanics.