One other thing, another way to add your custom assets to your map is to run the game in developer mode. Its not recommended to run the game like this all the time, but I do. Search the net how to start in dev mode, then open your map. Press the HOME key to bring up the add object menu. Like in the editor, go to Buildings, Industrial, Industrial Manufacturing and you will see your custom assets there and can select and add them to your map. If you name your assets and include a unique name, like your nickname or something, you can filter the object list at the top in the filter field to quickly list all your custom assets. REALLY important, when using the add object menu in the game dont click the x to close the add object window. Press the HOME key again to close it. If you click the x, it might not open again and you need to close the game and restart to bring it back up. Good luck have fun.