Manage licensewill open for you the Options window with the Rhino Nature section selected. At this point you can get a trial license by clicking the
Request trial licensebutton, an active internet connection is required. In case your device is not allowed to connect to the internet you can request a trial license using another device visiting the offline trial page and providing Device UID and Request Code obtained after clicking the mentioned button. After that, you need to transfer the license file to the offline device and open it via the License Key area context menu (Right-click → Open).
Add deviceallowing you to assign your device(s) to your license, after clicking it you will be asked to provide your Device UID. It can be copied from the above described section via the Device UID area context menu (Right-click → Copy) and pasted in.