Step 1: Once the Next Gen Math application has been added to your Roster Server and the appropriate sharing permissions have been set, head over to your ClassLink Roster Management Console
Step 2: From here you will need to select Applications > Add & Assign Apps
Step 3: Then select App Library and search for and add the Next Gen Math application
Step 4: Once you have added the application you will then need to assign app access to the desired roles for your site(s)