I just re-read your post, and I'm 99% certain that you needed to know how to load someone else's
presets into your copy of LumaFusion.
Quite simply, after you've downloaded them to your device, go to your Files app, and click the Export icon (I think it's sort of an upward pointing arrow), and choose Open With... and pick LumaFusion.
Then it will show up along with your other favorite presets.
I've watched pretty much all the vids on YouTube, and the ones which offer free presets, transitions, etc. will invariably always show you how to do this step-by-step.