First, you will need to copy your Dedicated IP Address from the Overview page of your control panel. It will be found under Server Information.
Start up your server, and open Starbound. Click on Join Game.
Select or create your character, then paste the Dedicated IP Address from your Overview page into the box. The port number can be found right under the IP Address.
Then, click Join server. You should now be connected to your Starbound server!
If you have followed these steps and are still having issues connecting, don't hesitate to contact our support team!