If you want to know what Lojban is, fetch the official Lojban brochure, which is part of the official Lojban web site.
If you want to learn Lojban, try Nick Nicholas and Robin Turner's lessons, and LLG's page about learning Lojban.
The texts available here are about issues that are not covered elsewhere in the literature. They are distillations of scattered pieces of information in the reference grammar, the textbook, other official and semi-official information from LLG, messages from the mailing list, and reported usage.
Be forewarned: most of the opinions expressed are my own.