Instead of USA Main Menu. You will instead have Chinese Main Menu, where instead of USA units, you see Chinese units protecting the region. So Chinese units willl defend off GLA now. Might be good, if you are starting with Chinese Campaign? This is the first shell map mod for steam workshop. If this gets enough feedback, i'll consider making GLA one also :)
If you dont see Chinese units on main menu, then make sure you have Maps folder in Command & Conquer Generals.
Also make sure the Shell map is inside the Maps folder, otherwise it will default to USA shell map.