Reddit mentions of The Flower of Battle: MS Ludwig XV13

Fiore is a great way to start. I'd recommend checking out https://duello.tv/ if you'd like really great instruction on it and are unable to find any local club near you. Devon Boorman runs Academie Duello and his interpretation is very good. His interpretation fills in blanks by adding in concepts from later Italian manuscripts written by Achille Marozzo, Ridolfo Capoferro, Salvator Fabris, Nicolleto Giganti, and Camillo Agrippa. So you'll probably find it easiest to pick up.

Guy Windsor also has several excellent books as well and he has some free video tutorials on his Youtube channel but they aren't as indepth as Duello.tv

Of course you should also purchase a translated copy of the original source, but if you're going to self instruct then gaining the insight from Guy and Devon will help you make a lot of good progress on deciphering what is meant. As with all of the source manuscripts there is a lot of information missing which has needed to be figured out through experimentation.

I would recommend this translation of the Ludwig / Getty as a source for Fiore https://www.amazon.com/Flower-Battle-MS-Ludwig-XV13/dp/0984771689/

My first recommendation would be to come down to Phoenix to learn first hand from Richard Marsden, otherwise, you can check: https://www.hemaalliance.com/ for close HEMA club affiliates.

You can also get a hardback, english translated treatise for $40 on Amazon: https://www.amazon.com/Flower-Battle-MS-Ludwig-XV13/dp/0984771689/ref=sr_1_1?ie=UTF8&qid=1523987594&sr=8-1&keywords=flower+of+battle

Aside from that, I'm not sure if there are any YouTubers for it but I really like Fiore's system.