If you are looking to install Nextcloud in CWP this is how to do it.
Goto Nextcloud.com/install and select Nextcloud Server
Scroll down and click on "Community Project
click on the here link to download the Web Installer file
Upload the Nextcloud Web Installer file to your server in your home directory (Public_html)
Create a database for the domain you wish to install Nextcloud in. Do this in the CWP mysql manager panel... Don't forget to create a user and give them full rights.
Now go to the domain name that you uploaded the Nextcloud scrit to and type: yourdomain/setup-nextcloud.php and follow the instructions.
Remember not to choose SQL light!
That's it... Nextcloud installed in CWP