Side-Power Dual Joystick Control Panel

All Side-Power control panels are waterproof (IP65), have an "activated" indicator light, a timed automatic shut-off, run on 12 or 24 volts, and feature no visible mounting screws. They also have a 2-button, child-proof “on” switch. The round back of the square panels fits standard instrument cut-outs.
• Dual Joystick Panels (2.76"W x 4.72"H) allow control of 2 thrusters with just one hand; saves dashboard space

The Side-Power website has helpful system set-up diagrams illustrating how components are selected and used in a variety of possible thruster installations.
When the webpage opens, select Side Power for the category, and select a "Type" of your choosing. "System Diagrams" will present you with a number of basic layouts for various thruster configurations - illustrating the parts you need for a complete system.
These diagrams also indicate where 5-wire cables are needed, and where 4-wire cables are used.

You might also find the "Type" named "Wiring Diagrams" helpful.
Regardless of the thruster system you are considering, the "Installation Manual" is an excellent reference. It illustrates many of the general factors and components needing consideration in any thruster installation, including placement of the tunnel, etc.