What difficulty level should I start with for a puppy or beginner dog?

Across r/Dogtraining and r/puppy101, the repeated advice is to start with low-confidence-friendly toys that dispense food with very little movement, then graduate to multi-step slide-and-flip boards once the dog understands the game. Several products in this list use a Level 1-to-3 design specifically so the same toy grows with the dog.