Start Terraria in Steam
Start the game on Steam, and wait for the title screen to appear.
Click "Multiplayer" on the title screen for Terraria
Click "Join via IP"
Select your Player Character
On the following screen, either create a new character to use, or select one of your existing characters.
As soon as you select a character it will go to the next screen.
Enter IP address of your Server
Enter the IP address for your server where the blinking cursor bar appears. The IP for your server will be shown on the "Overview" tab of the Nodecraft control panel, below all the graphs showing things like CPU and RAM usage.
If you have previously entered an IP address on this screen, it will be shown directly below the blinking cursor bar, in grey text. You can click on any of those links to go straight to that server (as long as that server is actually running).
Confirm Port Number
On the next screen, it will ask you to confirm the port number. The default port used is "7777," and if you have not changed it to something else, simply click "accept."
The screen will show "Connecting to," followed by the IP address, and you be connected to the server!
You'll appear in the game, and now it's time to run from the slimes!