How to set up Ubuntu Server?

You need an OS for you server and we've chosen the latest Ubuntu Server LTS release for you. Here is how it should get installed and configured.

Download the latest Ubuntu Server 22.04 LTS image by clicking here (this might take 30min because of slow download servers)
Use the already downloaded image to create a bootable USB-stick by following this guide (the guide is for Windows, but guides for macOS and Ubuntu are referenced there)
Connect a LAN-cable to your server
Connect the USB-stick to your server and power the server on. The server should then automatically boot from the USB-stick. If it doesn't, press [F10] which should open the Boot menu on Intel NUCs. (And type in the password again).
Since it is necessary that you configure certain things correctly, we have prepared a slideshow which makes it easier for you to configure Ubuntu correctly. Please click here to start the slideshow. Otherwise, just continue with the steps below
Select the correct language for the installer
Select the correct Keyboard layout. This is has great importance!
Confirm the default Ubuntu Server installation type (and not minimized)
Just use the defaults in network connections
Don't configure any Proxy address
Use the default Mirror address
During Storage configuration, activate the option to Encrypt the LVM group with LUKS, enter a difficult Passphrase, confirm it and store it at a safe place.
(Difficult passphrase means at least 16 characters long, containing small and tall letters, digits and special characters)
(Please note: The installer doesn't check if the passwords are equal so please make sure yourself. Alsoy you should only use a password with characters that are the same on a QWERTY keyboard layout because of a bug in Ubuntu. Here is a link to one: click here)
Confirm your Storage configuration
Set up your Profile: recommended as name and username is ncadmin. Recommended as Your server's name is nextcloud. Also type in a password. This can be simple because you will change it later on, again, but remember it! Please note: The installer doesn't check if the passwords are equal so please make sure yourself!
Choose to Install OpenSSH server
Do not install any of Featured Server Snaps
Now wait until Ubuntu is installed and you see the button to Reboot. Press it to reboot.
You should now remove the Ubuntu USB-stick if not already done and press [ENTER] to continue.
During the boot process, type in your LUKS passphrase and press [Enter] to confirm.
(If it doesn't accept your LUKS passphrase and you are sure that you enterd it correctly, most likely you experienced an Ubuntu bug. In this case, try to enter your password as if you had an QWERTY keyboard. Here is one example click here
Additionally, please make sure, that Capslock isn't activated.)
Now type in your username (e.g. ncadmin) and pasword
If everything is correct, you will now see an overview of Ubuntu also containing the IPv4-address of your server.

note

You will need the ip-address in the next step!