In my story I have an every-man, lets call him Jim.
Jim never finished high school, works as a night guard, and spends his time drinking beer, watching TV, surfing the internet and hanging out with his buddies.
He is mysteriously transported into the paleolithic age, and accepted by a tribe as a curiosity. He doesn't have any of his technological tools with him, only his clothes.
Assuming that Jim has a lot of knowledge of technologies that could be useful to his new fellow tribesman, such as bow and arrow, hide shields, metallurgy, farming etc. But he never tried to actually use any of them, his knowledge is merely theoretical from watching history documentaries and reading on the internet.
What kind of things could Jim teach them, or help them develop together?
The tribe technology is at later stone age level, they have wooden spears, fire, sewing tools, fish hooks.