.crm files are saved Rooms. In older versions of AGS, room0.crm had to be named intro.crm. You can make a template room called _blank.crm which will be used by the New Room function. Every AGS game must have at least one room to function. The first room that is visited upon starting an AGS game will be determined by the initial player character's starting room. For AGS to see them, room files must be saved as roomN.crm where N is a decimal number.
You can save a room and place a copy of the CRM file in the Compiled folder, and it will override the one in the .exe, however this is quite a faff to remember to do it every time you need to.