Hey anon!
Resource guarding is a pretty serious issue. Even if it’s mild right now, it can become something serious very quickly. We cannot responsibly give you advice over the Internet without seeing your dog in person – you should get a trainer to come in and evaluate your dog.
There are certain blogs that will create training plans in exchange for commissions, so you could check with them. You can also Google resource guarding to find tips to help keep it under control until you can get a professional in.
-C