cant add a script because of monobehaviour

Guys i´m new to unity and scripting itself so i dont know how to solve this. i wanted to apply AssetPostProcessor on my model and this had popped up: Cant add script behaviour ColliderOnName. The script needs to derive from monobehaviour

An AssetPostprocessor is an editor script. It can’t be attached to anything. It is executed automatically when you import / reimport any asset.