Hi, If you want to add a new website to your license do the following after you start it on WordPress :
Install the Free plugin – Go to your WordPress Dashboard to Plugins > Add new, search for Elementor and install the plugin.
Install the Pro plugin – Go to https://my.elementor.com/subscriptions/ and click on Download Zip to download the plugin. Now go to your WordPress dashboard, go to Plugins> Add new and press on Upload plugin to upload and install your Zip
If you are using Mac please follow these instructions to download https://elementor.com/help/downloading-elementor-with-safari-on-mac/
Activate your license – On your dashboard go to Elementor > License and press on Connect & Activate to connect your website to your license.
If you need to connect to the library- check this Connect To Template Library