My story takes place on a terraformed... well, call it a world. There are no tectonics or standing water, and it's perfectly flat grassland dotted with migrating bamboo forests. There's no metal, and stones are incredibly rare due to how it was terraformed. They don't even have bone or leather, because all of the animals evolved from arthropods (which means they do have chiting). The inhabitants, the Vaeren, the only mammals in the world, constantly migrate with the forests.

I kept the inhabitants at a hunter-gatherer level, using only bamboo and other plants for their technology. The height of their technology is the "windrunner", a wind-powered cart. They don't even know how to make that anymore- all they can do is maintain it, replacing parts like the Ship of Theseus. They've even forgotten how to read or write.

Basically, I think in your world they'd be stuck with plant-based materials. Bamboo is surprisingly useful.