First this is the wrong place for questions. These should be in the main creation and customization forum, this place is only if you publish a completed map. I have asked a mod to move it.
Second : you need to create a scenario folder for your map with the same name. In this folder you should create an Art folder then a subfolder called "terrain". For the complete hierarchy it is easy, just look at how it is done in Conquests folder, you must do the same.
Then add Snoopy's terrain in that folder and make a link in your scenario/map in Scenario Properties/Scenario/Scenario Search folders : where you put the link to the folder with the same name as your scenario.