If you use "Save > For This Folder" from the Folder Options dialog then it will only affect that folder. (If you do other things, it can affect other folders, of course.)
You might want to skip Folder Formats: Detailed Guide if you want a deeper understanding of folder formats.
By the way, Layout has a special meaning in Opus, and is different from a Folder Format, which is what we are talking about. To avoid confusion in other threads, it's best to only use "layout" if you're working with Opus layouts.