I am no expert on edible plant species, but I do know of many plants that can be used for various purposes. I am finishing up some video on another topic, but I will do a write up in the next week with some tips and points of concern once I have a bit more time ... unless someone else knowledgeable wants to field this first.
In the time being, I recommend you scour the library or book stores and pick up some specific material on edible species relevant to your own area. A lot of books have general guidelines, but often are loaded with plants that you may never encounter. You will have to be specific, and then spend some time in the field attempting to identify various species.
There is also a really good Youtube channel... Eat The Weeds that is an outstanding resource and a great place to start.
YouTube - EatTheWeeds's Channel