A specific guide to do exactly what you want… I’d recommend spending a while with your favorite search engine browsing examples. There are so many combinations with tools like Drafts and Flow that you are unlikely to find an exact walk through, but you can probably piece together something from a handful of them.
The key thing to know is where to find the documentation for each:
However, do note that Flow is just like Zapier/IFTTT in many respects and for most uses is just a step by step wizard like build of an automation.
Hope that helps.