In Roll for Shoes Prison Module, how much hp should each character have?

The "Prison Module" module by Mongoose systems (given out free in 2020) offers a variant rule for Roll For Shoes involving wounds and scars: you take a wound when you are attacked, hit by a trap, or fail a dangerous action, and if you take a second wound in the same place, it becomes a scar that cannot be healed anymore. It says that if you take as many scars as you have HP, you die. However, I cannot find in the module anywhere how much HP you have. Should I just have them roll a d6? Do I set an HP level based on their class? Or what was the intent here?