Hi I want to create a mobile game which is kind of a Strategy game and I dont know how to create a building, an when i touch it , a UI appears and there is a upgrade button and if i click it, the mesh of the building changes and stuff like that. So can anyone tell me how to script a “Uprgade system”?
No one will be able to give you a short answer on that since you ask how to build a game.
Try breaking up the components you need, like how to model a mesh.
Then you need to learn how to spawn a instanced static mesh and replace with different meshes.
You also need to learn how to make widgets, how to spawn them where and when needed.
Google is a fine and quick way to search for tutorials. Good luck!