Once you have your license key, please download and use the Foundry Licence Installer (FLI) to install it on the relevant machine. The FLI will check that the licence is valid and then write the licence file to the correct locations on your machine so that the software can find the licence.
To install the licence, please copy and paste the licence key (or drag and drop the license file) into the FLI window and click on the Install button.