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>")

change the machine name:

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

enable force_color_prompt=yes in file ~/.bashrc and /root/.bashrc