NextcloudPi: How to install Etherpad (Lite) / Ownpad

Hi there

I was wondering how to install the Ownpad / Etherpad app?
Is there any tutorial for the NextcloudPi?
I don’t like any experiments (by my own), because I’m happy with my running config and also kinda noobish with extra installs.
Is node.js already installed on the NCPi?
What else do I need to know?

Thanks so much.