Login to ubuntu 20.04 sever.
Run the following commmand to download nextcloud.
snap install nextcloud
root@vps:~# snap install nextcloud
nextcloud 18.0.4snap1 from Nextcloud✓ installed
Now type your IP address in the URL to launch the nextcloud.
Replace the server_IP with your server's actual IP Address.
You will have to create admin account for NextCloud
Enter the username and password which you want to set.