Creating a comprehensive module template

I want to find an article on developing a 'comprehensive module template' that would include branding colors, fonts, slide layouts, etc.  I keep finding this same kind of statement "first build a new project the way you want it to look and behave. Then save as template." I want more detail in that first step! I have found articles on creating font themes, color themes, custom heading styles based on themes, slide masters, etc. but I can't find one article that ties it all together, "and in the darkness bind them" 🤓

Use case: we design training for software and there are branded levels of training. I want a template for each level so designers can apply the template with fonts, colors, layouts, styles defined and start working!

This can't be that hard to find, but man I can't find it!