I've been foraging for about 6 years and was taught originally by Steve Brill and his walking tours. His city slicker origins, his passions for foraging and culinary arts, and his uncanny abilities to explain the joy, the cuisine, the empowerment, and the necessity of sustainable wild edible foraging are surprising and inspiring. I literally trust him with my life when it comes to foraging.
Steve Brills apps have added another dimension to basic guided foraging ( plan identifiers, uses, times to harvest, habitat, warnings ) by adding outstanding pictures of these plants throughout the progression of the seasons.
It doesn't get easier than this. The free apps are thorough intro's to wild food foraging, and the full apps will make trips to the grocery store feel kind of redundant.