Until Cloud Poodll for TinyMCE becomes available from Moodle.org, you should install it via ZIP file.
The page explains how to install a plugin's ZIP file from Github.
After installing Cloud Poodll for TinyMCE you will need to add your Cloud Poodll API user and secret on the settings page. You can find your API credentials in your member area at :
Then you will see 2 new icons when you open a page with the TinyMCE editor.