Resources? Anything by Samuel Thayer.
Nature's Garden. The Forager's Harvest. Thayer only writes about plants that he personally has found, and prepared for eating.
And then there is Green Deane. He has a
free forum to post pictures of your finds, to get confirmation on your plant identification. He also has a multitude of articles
here. Then there is his
Youtube Channel. If you live in the Florida area, you can attend one of his walks, for a fee.
As for where to forage... for practicing identification, try a state park. There are rules about what you can harvest, maybe even an outright ban. Maybe go for a drive in the country, again for identification purposes, walk along a quiet road, see what's in the ditch.
There is nothing quite so satisfying, as when you can identify a plant at 45 miles an hour by its winter skeleton!