What attack can humans undertake without metal?
To be honest, the players didn't have much of a clue either.
In the early stages of human warfare when the strength of metal wasn't very high, wooden products were indeed the mainstream.
But as far as history goes, humans have probably never hunted such large land creatures before, and moreover, these are not creatures of flesh and blood but rather enormous beings with steel hides.
To put it formally, in the absence of any supernatural enhancements, the weapons in the players' hands would likely be less hard than the enemy's hide; a direct confrontation, although not necessarily causing mutual destruction, could at the very least be described as throwing eggs against rocks.
Adopting common human combat methods would only result in the annihilation of a group.
The players were, of course, well aware of this.
They created some simple war machines, such as trebuchets.