There is no guide yet. An in-game guide that could be enabled/disabled in the settings would be nice to have. I might implement one when the game/season is finished, but not before.
It is possible to stay up until Ada steps in and interrupts the fight. That way you don't win the fight, but you don't actually lose it either - it's more like a draw, I think. (By the way, Beth likes it if you fight the man and Ada likes it if you don't).
The easiest, safest and most common solution would have been to make the main character a strong and good fighter, but I wanted to try something different. I'm aware that not everyone likes it, but in this game the main character is just a regular guy who cannot fight well (at least in the beginning of the game). Later in the game the main character will face more dangerous opponents than the man on the beach. Since he cannot really rely on his fists, he needs to find other means to survive. That will make the upcoming action scenes challenging but also interesting IMO.