There is a manual available, it comes with the robot and is immediately lost by the first technician to stumble upon it, never to be seen again.
We aren't allowed to post links to FANUC owned manuals or copyrighted materials here, but you can take a look at my open source ebook on TP programming. I'm *specifically* writing it out on my own to ensure it never angers FANUC's legal department.
So far I've written pages on about a third of the TPP materials, and I add two to three pages every week. Each new concept is introduced in lab experiments as well, with step by step guides on how to apply them.
So far, nobody has actually figured out why FANUC doesn't release free manuals for their products. You'd think they would, as someone is FAR more likely to purchase FANUC robots at their company if they can easily obtain all the required documentation.