1. Sign up on Poodll.com
To use Poodll EnglishCentral and other Poodll plugins you will need an account on Poodll.com. Sign up for one of the paid subscriptions at https://poodll.com/register/poodll-englishcentral-free-trial
2. Register your site URLs
Poodll registers your sites as they appear in your Moodle site configuration file. Your registration is checked against that when Poodll runs. To do this, go to http://poodll.com/member and enter your Moodle site's URL/domain (start from http/https).
Most paid Poodll plans allow you to use a wildcard '*' in place of the www (or other subdomain) to enable all subdomains, e.g https://*.mycoolsite.com . NB The URL needs to begin with "https" or "http"
Poodll also generates a registration code for each registered URL beneath the URL field. That is for the old system, if yours is a new install (or updated since December 2018) you do not need that registration code.
3. Copy your API User and API Secret
Poodll uses your API username and API secret to allow your site users access to Poodll. You will find the API username and API secret on the "API Creds" tab of the https://poodll.com/member page.
4. Set the API username/secret and registration code
In your Moodle site, in the settings page for the Poodll EnglishCentral plugin, you can add the API username and secret.
Poodll checks every 12 hours so for any subscription updates. So when you renew or upgrade your subscription (eg from free trial to a paid one) the Poodll plugins know about that automatically. You do not need to update any settings for them. But you can speed things up by pressing the "Refresh license information" link. This will tell Poodll to check immediately.