Documentation has previously been added to the GitHub Wiki for the ConnextCMS repository, but the documentation has now been converted to HTML and incorporated into the repository itself. It can be found in the /public/documentation directory. This will allow documentation to undergo the same version control as the rest of the code. A live copy of the documentation can be found here.
In addition, the ConnextCMS Core features are now documented inside the application. Click on the question mark in the upper right corner of the ConnextCMS dashboard to get help on the current screen you are working with.