This should be an upbeat song in a scene after battle where the soldiers discuss the battle and brag about how well they did. See scene 22
They laugh about how they fooled Chicho and are high with the excitement and their victory. They all brag about how many they shot, and someone might even laugh that they claim to have shot more soldiers than there were. At a campfire they will have guitars to strum and objects that can be used as percussion.
There was a term commonly used to describe the guerrilla revolutionaries such as Fidel Castro, Camilo Cienfuegos and Che Guevara- ‘barbudos’: bearded ones. You could write a song about how they have grown their beards while fighting in the mountains – although Raul never did grow a beard. They could laugh and brag about the length of their beards and what they symbolise.
Extract from Wikipedia:
Barbudos are bearded revolutionaries. The term was coined to describe the rebel forces of the Cuban Revolution. The barbudos, as they became known, did not drink, did not loot, conducted themselves as if they were saints. No army had ever behaved like this in Havana.”
Another place for a campfire song is scene 29 much of which can be set to music.