Many people have been complaining that Firefly "has no documentation" and/or they can't find it, but Firefly has a bunch of docs and tutorials linked to here in this thread.
There are many great Tutorials for different features of Firefly:
In the about panel of the Firefly engine there is a OPEN TUTORIAL button which contains Chocobreak 3D and an in-development First Person Shooter written tutorial.
Please login to see this link. - Chocobreak 3D is a written tutorial made by Clickteam to introduce people to Firefly and bridge the gap between 3D and 2D. (Note: Files are located in \Clickteam Fusion 2.5\Tutorials\Firefly\Chocobreak3D.
Please login to see this link. - The in-development First Person Shooter tutorial made by Clickteam to further your knowledge and explain some of the more advanced features of firefly. (Note: Files are located in \Clickteam Fusion 2.5\Tutorials\Firefly\FPS.
Please login to see this link. - The Clickteam Library also has some Firefly info.
Please login to see this link. - The Captain Quail channel has video tutorials for many things, including first person movement, third person movement, and importing.
Please login to see this link. - There is also a Firefly YouTube playlist.
Please login to see this link. - The ClickWiki has information on Firefly and the different objects:
Please login to see this link. - You can always get quick help from other Clickers and the Firefly developer in the Firefly channel of Clickteam Discord Server - The new home of Click Converse.
Also, there's some Firefly example games and source available here: Please login to see this link.
There's also a thread with some more videos, they're probably all in the channel and playlist above but you might want to check it out: Please login to see this link.
Squatter also made a collection of Firefly examples available here: Please login to see this link.