After registering for an account you can set up monitoring for as many sites as you wish. From your main home dashboard simply click the 'Add site' button, enter the site name and url, click the submit button and your site will be created. Be sure to enter http:// or https:// at the beginning of the url to ensure it is a valid url.
You can find the API key under your site settings page. You will need this for authenticating when sending logs to the API.
Now that you have your API key, you can install and activate our plugin following the instructions here.