The Lianja App Builder is the development environment.

The Lianja App Center is the desktop client for published and deployed Apps.

When you install the Lianja App Builder, one user is already created - the 'admin' user, with the same password: 'admin'. You don't need to use these login details when you start the App Builder - you will be logged in automatically - but you do need them to log into the Lianja App Center or when you log out of the App Builder Home Workspace and want to login again without exiting the App Builder.

For more information on Users and Roles, please see the Lianja Documentation Wiki here.