[AndreiWow]

How to map in an interior using editor.exe?

[RadioActive26]

Go up in the sky and create a floor then add the walls and a roof, after that go inside and start adding furniture or whatever you like.

[AndreiWow]

I mean inside a gta sa interior, example inside police station.

[RadioActive26]

Ah, in the right side menu enter the coordinates(Y,X,Z) of the interior which can be found here: https://sampwiki.blast.hk/wiki/InteriorIDs