Richard has converted many of the original example programs I wrote many moons ago for the BB4W version of GfxLib (or strictly speaking, GfxLib2), and I believe they provide a useful source of information on how to use the new GfxLib 2D game library which now comes as standard with the BBCSDL package (version 1.26a onwards).
Here is the link to the zip folder containing the examples:
http://www.rtr.myzen.co.uk/gfxlib_bbcsdl.zip
I'm very grateful to Richard for providing this resource, it was surely quite some effort on his part, and I for one will certainly find them very useful!