Where to start how to power

Hi guys
I am trying to build a small generic GA cockpit system that can easily be setup on a desk, and packed away when no in use.
At the moment I am looking at a simple modular design comprising of a central instrument panel encasing a saitek cessna yoke with an I-PAD replicating a glass cockpit (using RF Cockpit app), on the LH side of the yoke I have a switch panel containing the 5x 12v (illum when on) LED toggle switches( bat, avionics, fuel pump, beacon and Pitot Heat) 1x 3 pole 4 position rotary switch for the magnito (Off 1, 2, both) and 1x momintary for as a start button (as req for A2A piper commanche) on the RH side of yoke I have 5x 12v illum when on toggle switches (Taxi, Nav, Landing 1, Landing 2, Strobe)
part 2 will be a throttle quadrant/pedistal which has 2 saitek throttles (1 that is part of the yoke and an additional usb variant) housed in the same unit I have built a working landing gear lever plus LED indication/transition light system using an Aduino uno and a script source from JIMNZ and the wonderful Link2fs_multi software, this currently is the only part of the project that is wired up and powered.
the hardware I have available currently is:
1x ATX power supply (not yet part of the project)
1x BUO836X 12-bit joystick Board
1x Arduino UNO
plus various resistors pinboards, breadboards, LEDs and switches.
Thats my intended plan as a first project, I would appreciate advice and guidance as to how to power the project..I have little knowledge about electronics and electrical circuits. I unkowingly bought 12v illuminated switches before I realised that the I/O boards use 3.5v upto 5v via the usb connection and upto a max 12v if using an external power source (for the arduino at least) and I would assume that it would be a folly to hook up strings of leds illuminated switches drawing all the power via the usb supply. How can I overcome this and create panel by panel power supplies without burning out the I/O boards or more importantly my PC.
many thanks in advance
Maggsy