Hey Adam, the easiest way to do this is just to save a FL Studio Project (.flp).
You'd use that as your template.
Here's how it'd work:
- Create a template with your melodies / drum loop
- Copy the project to a new file + Rename it
- Open it up, then change your sounds!
You can now re-use this template, create a new project, then modify the sounds to your liking.
You can even add this as an actual FL Studio template so you don't have to do the copy & rename found in Settings -> General -> Default template.
You load templates into:
Documents/Image-Line/FL Studio/Projects/Templates
I think that will be the easiest solution for you here.