Login to the server via SSH as root

Install sudo, create the main user, and add him to the sudoers group

# apt install sudo
# adduser <user>
# vi /etc/group (add <user> to line "sudo:x:27:<user>")

(VPS) change the machine name:

sudo edit /etc/hostname
sudo edit /etc/hosts

enable force_color_prompt=yes in file ~/.bashrc

copy /home/user/.bashrc to /root and modify PS1 prompt color (32m –> 31m)

Configure SSH Access

Install UFW Firewall

Disable root login by changing file /etc/passwd from line 1 to line 2

root:x:0:0:root:/root:/bin/bash
root:x:0:0:root:/root:/sbin/nologin

Additional packages

$ sudo apt update
$ sudo apt install vim
$ sudo apt install zip
$ sudo apt install rename
$ sudo apt install rsync

Change visudo editor

$ sudo update-alternatives --config editor