The works are quite easily available, and facsimiles of Marozzo’s Opera Nova can be found in many other places than the ones listed here. These should be enough for you to get started! I only post translations in this list that I use myself and have found good and complete.
Achille Marozzo
Facsimile of the 1536 edition
Facsimile of the 1568 edition (PDF)
Transcription (PDF)
Transcription (online)
Illustrations as a single, zoomable image
Antonio Manciolino
Facsimile
English translation by Tom Leoni (book)
Transcription (book)
Transcription (online)
The Anonimo Bolognese
Transcription (book)
Giovanni dall’Agocchie
Facsimile
English translation by Jherek Swanger (PDF, includes books I and II, that are relevant to swordplay)