The following guide will show you how to get sand in Farthest Frontier. You cannot instruct your villagers to start scooping up sand from any random dirt road. You need to build a Sand Pit to ...

The better Shovel you use, the more Sand you will get from digging. You'll also need some Granite, which you can find in abundance pretty much everywhere. Once you've got the required resources ...

Furthermore, some enemies drop Refined Iron Sand after defeating them in Chapters 2 and 3. However, this is all left to RNG ...