[HOWTO] Install Collabora on a self Nextcloud install for dummies

Hi,
I have very very very few knowledge of programming and installing. For example, I barely understand the instructions written here.
I have Nextcloud on a server (Cloud hosting) and I would like to have Collabora.

Is there any way to understand better how to do it?

Thanks

Here:

https://www.allerstorfer.at/nextcloud-install-collabora-online/

So this is the latest instruction the, for NC15 https://www.allerstorfer.at/install-collabora-online-on-nextcloud-15-with-ispconfig-3-on-ubuntu-18-04/

Ist this still needed for NC 18? I though since “nextcloud hub” is everything included?