Poodll WordCards is a new plugin and still not released on the Moodle.org plugins directory. For now the best way to install it is to download the zip file and upload it to Moodle.
1. Download the plugin zip file
You can download it directly from this link:
2. Go to your site’s plugins installer and install it
Your Moodle site has a handy system for installing plugins from zip files. From the site administration menu, go to:
plugins -> install plugins
Begin the Installation of the plugin, by uploading the zip file into the file area displayed.
Moodle should detect the plugin type automatically.
Let Moodle lead you through the installation. You can leave most of the settings as their defaults. But you must enter your Poodll API user and secret.
You can get your Poodll API user and secret from the Poodll member's area at: https://poodll.com/member
At that time be sure to also register your Moodle site URL. See here for more details: