- Check existing users :
cut -d: -f1 /etc/passwd
- sudo adduser user_name
- add newly created to root group
sudo usermod -a -G sudo user_name
- change current user to new user
- cd to home dir of newly created user
- run
mkdir .ssh
- secure it by
chmod 700 .ssh
- to create authorized_keys file run
touch .ssh/authorized_keys
- Copy your public key in clipboard
cat >> .ssh/authorized_keys
- Paste key and hit enter save file
- Now from client machine try to connect server ex. ssh private_key_path username@domainorip