You can assign your license to a machine by simply signing into the Maxon App and choosing the license you'd like to use to activate/assign to it. You can also release your license, and use it on another computer.
Ensure you have the latest version of Maxon App, downloaded here.
Then go to the 3 dots by the product you own, and click "Assign"
If your license is already being used by another machine, you can release it from the other machine;