Bunnies & Burrows help!

Hello, I am running a Bunnies & Burrows 3rd edition 1 shot campaign (frog god games). I am having a ton of trouble figuring out the language around “professional level” and could use help. The game features the ability to spend advancement points to level up specific levels, but you have no obligation to dump these APs into your key trait. So for instance the key trait of a fighter is STR, but when the game book references Fighter Level 3 (professional level), it doesn’t specify if this means a rabbit fighter that has reached STR level 3 or a rabbit fighter who has received 3 APs regardless of spending. This creates an issue where I don’t know how to build foes at the proper level. And if I choose to start my party at level 3 in their primary trait, how many (if any) additional APs do they get? I might be missing something but I can’t find this info anywhere.