How do I replace a standard component in my design?

When you start with a standard template, your 3D design often contains a few basic components. Think for example of a skybox (this is the image around you), the ground, or a shop or building you want to furnish.

To prevent you from accidentally moving or modifying these objects, they are locked by default. But that doesn't mean you can't customize them.

A standard template with a building that is locked

For example, how do you replace the building in the locked folder shown above?

Select the folder, and uncheck the 'Lock' box to unlock it.
You can now remove the building and the roof, just like any other object
Place another store building and roof in the space, make sure to put these objects back in the same folder
Select the folder again and check the 'Lock' box again to lock the store again