Hmm. To be honest... while you might have a chance setting it up if someone provides you with a script, there's little chance you'll be able to keep it running in the long run. At least not in a fast and secure manner. Nextcloud is pretty easy to setup and also pretty easy to maintain but you might want to learn linux/unix and networking basics first. And I totally encourage you to do so as it's a lot of fun and you'll learn the wonders of a unixish os.
You need to ssh into the vps, harden it (things like choose a good root password, install fail2ban, turn on the firewall and such, then install a webserver and dbms (like apache and mariadb or mysql), php with all extensions nextcloud needs, then download nextcloud, unpack it into the web root, then open that url in your browser and go through the setup process. Check this out: https://docs.nextcloud.com/server/16/admin_manual/
Also there are other ways to use Nextcloud like have a package manager (yum, apt, etc...) install it, fire it up using docker containers or have an appliance like a NAS install it automatically. Also, some hosting companies offer ready to install "apps", one of which surely would be Nextcloud.
Hope that helps a little.
