apt update -y \
  && apt install shadowsocks-libev -y

shadowsocks-libev service has been started, the default configuration file: /etc/shadowsocks-libev/config.json.

Edit configuration file and restart service:

systemctl restart shadowsocks-libev

Check the status:

systemctl status shadowsocks-libev

How to Set up Shadowsocks-libev Proxy Server on Ubuntu 16.04/17.10