Since Citesphere uses Zotoro as backend, you need a Zotero account to use Citesphere. You can create one here. Once you have a Zotero account, go to Citesphere and click on "Sign Up". You will be taken to a registration page. Enter your information and click "Create Account".
An administrator will have to approve your account before you can start using Citesphere. At the moment, you will need to let the administrator know yourself that you've created an account that needs approval (this will be changed in the future!).
After your account has been approved, you can login to Citesphere. The first thing you have to do is connect your Citesphere account to Zotero. You do that by clicking the "Connect Zotero" button you should see after you have logged in to Citesphere.
This will take you to the Zotero site. Login to Zotoro and approve the request to connect Citesphere to Zotero by clicking the "Accept Defaults" button. You should be redirect to Citesphere where all your groups should show up (note that this might take a little while depending on number and size of your groups).