The best explanation of Humanianity is given at its Home page, at Humanianity.com.
The new addition to the site has been the Belief Manual component. The link to it is at the bottom of the Home page.
Think of the Belief Manual as a "Bible" for our species, one that can be accepted by everyone because of its nature, that is so much different from all other religious texts. These crucial differences are also explained on the Home page.