To install a new role, first you have to download and install the update to Server Manager. Then, open Server Manager, and ...

To install a new role, first you have to download and install the update to Server Manager. Then, open Server Manager, and click Add Roles.   If you install a new role without installing the Server Manager update, the role will not display in Server Manager.    If you do not want to update Server Manager at this time, click Cancel. To update Server Manager, open Windows Update, click Check for updates, and then select the most recent Server Manager update listed.