Firstly you need MySQL server and MySQLWorkbench, I suggest a quite stable version MySQL 5.7. As for Workbench I suggest MySQLWorkbench 6.3 because higher version may cause compatibility issues.
Edit mysql.cnf, I found mysqld.cnf under/etc/mysql/mysql.conf.d, find bind-address = 127.0.0.1 and comment it out
#bind-address = 127.0.0.1
On your server, mysql -u username -p
Add new mysql user
GRANT ALL ON *.* to user@'IP' IDENTIFIED BY 'password';
'IP' I suggest use '%' which means allow all ip connections. Then refresh system
FLUSH PRIVILEGES;
exit and restart the mysql service
sudo service mysql restart
Click the plus button on the home page, fill in the server IP address, username, password(your mysql password on server), wish you success!