Like many open-world games, your map in Sand Land is mostly hidden at first, unless you manage to fix Radio Towers scattered in different areas of the world. Repairing these monuments to old technology will help you track down other interesting areas of regions you explore. However, you need to have the right materials for certain Towers to get them back into working condition.

https://screenrant.com/sand-land-how-to-fix-radio-towers/