This link opens up the Building Template Manager (there is a corresponding button on the Main Toolbar). You can create new templates from scratch, or copy/modify existing templates. Once you have created the Proposed Building (and assigned some room activities), the list of Templates will be extended with Green Mark regulation templates, which cannot be modified, but can be used as a starting point for deriving your own templates from.
Once you have created a Template, it can be assigned to the currently selected zones within GM Compliance Mode (Singapore compliance module) using the appropriate toolbar icon: