Thank you for your message.
You don't need to register Hosts. You need to register the Viewer only. You can do it in the License Key Storage, here's a related article
on how to get a free license key.
Then you can add up to 10 endpoints to your address book.
Here's a related article in our Documentation: https://www.remoteutilities.com/support/docs/license-types/#Free_license
Hope that helps.