Hi K,
I think the best advice and probably the advice everyone would give you is search the forum for answers that 'suit' your project best.There are many,MANY builds by people that can serve as the best tutorial from a to z and often with pictures to support the description.
A good thread with tips and files would be JFcustom's foam files thread.
A few tools to get you started,regardless of whether you wish to build in foam,fabric or cardstock:
-Pepakura Designer ; free software that opens up any model that you wish to use in any project (.pdo / .stl / .3d files).Download the latest version from Tamasoft website;
-(Selfhealing) cutting mat ,for cutting your foam-/cardstock templates;
-Box cutter/hobby knife/Exacto blade with a sharpener
https://m.youtube.com/watch?v=ttIk4TZP3q0
-(metal) ruler
-heat gun; for heat-shaping and sealing your foam (get heat-resistant gloves,because the foam will heat up considerably)
-glue gun/contact cement; for putting together your foam templates
-sharpie/pen to outline your paper templates on foam before you cut them
-Impasto Gel 1 by Lascaux.Hardens your armor with plastic-like coat (3 coats advised) and when mixed with PVA white wood glue it becomes a little bit more flexible
https://m.youtube.com/watch?v=StDwK-tKUuo
-Acrylic paint
This is one of many ways to go about your creative business,but I believe it is the most environment-friendly method and the one I personally would use.
And to top it off,a few Green Arrow models (bow included) to help you on your way (open up and unfold in Pepakura Designer):
https://www.models-resource.com/mobile/injusticegodsamongus/model/13927/
https://www.models-resource.com/mobile/injusticegodsamongus/model/15664/
https://www.models-resource.com/mobile/injusticegodsamongus/model/12670/
Good luck! Looking forward to your first build thread