Implant in their brains how important it is to walk steady at your heel without the need of a leash. It should be second nature that they stick to your right or left side when walking anywhere. No one likes a dog that runs uncontrolled especially afield. Whether you pick right side or left side is up to you. This is something you can train anywhere.

Good luck and enjoy the training, train your dog the way that makes sense to you. There is no cookie cutter way that dogs have to be trained. Enjoy it, it’s really fun watching stuff click in a young retrievers head as you probably already know.