Download Ubuntu 18 here: https://releases.ubuntu.com/18.04.5/
mount the downloaded Ubuntu 18.04.5 .iso file
reboot your system
select a language (english is fine)

select “Install Ubuntu Server”

press y

select yes if you have “ö”

press “ö”

select no for the weird e

select your primary network interface

enter your hostname

enter the full name for the first user

enter the username

enter a complex password

if the autoselected timezone is correct select yes, otherwise select no and chose the correct location

if you had a server before, select unmount partitions

select “Manual” and then set up LVs (LVM)

select your disk

partition the disk -1GB space (for /boot)

select “Primary”

select “Beginning”

set use as “physical volume for LVM” and select “Done setting up the partition”

select the “1 GB FREE SPACE”

select “Create a new partition”

continue with the 1 GB

again choose “Primary”

set “Ext4” and mount point “/boot”, you can also set the label as “/boot”

select “Configure the Logical Volume Manager”

select “Create volume group”

choose a name for your VG

and place it on your correct partition

select “Create logical volume”

select your VG

choose a name for your LV

then select the size (if you have the chance to extent your PV/VG, you should create a 10GB root and some fitting /etc /var /home mounts as well. in my case I cannot extent it so I chose to use all on /)

select your new LV

set “XFS” and the mountpoint “/”

it should look like this now, if so, write changes to disk

during the next loadingscreens you will be asked for a proxy, if you dont have one leave it blank, otherwise insert your proxyip

select “No automatic updates” otherwise your OS will install updates without your interaction

choose “OpenSSH server”, you can install the other software later

wait..

select “yes”

Yay!

eject the disk/ iso
reboot your machine
fully update your OS
configure your network interface, sudoers, ssh and consider fail2ban
Network
Sudoers
SSH
Fail2Ban