Need a hand wiring a gauge

HI guys been a while since i was on here last, hope your all well :)

Well my window broke so i tore apart the door took me a while coz its so damn complicated found the problem but its too late to get the parts. So i decieded to thrown in my boost gauge. Everything was going perfect till i realised i dont know how to wire the thing up.

Its a calibre gauge and the instructions are rather ****ty but it has 3 wires
-White 12V ignition switch
-Black Vehicle ground
-Orange 12V dash lighting

My gauge mounts in the drivers side air vent so i have plenty of wire where the fuse box is, but unfortunately i dont know what to connect to its all french to me. ive looked all over the net to find out what to do but my gauge seems different to others i come across peeps with 4 wires, tieing 2 together putting them in odd places... Confused cars in pieces was great fun tearing it down more fun having it back together.

Also is it better to tap into the fpr or dv for the pressure reading??

Thanks
Ante

Also i did read the guide here but the pictures wont show so i could only get so far with no sight

I wired my boost gauge into the dash dimmer switch so the gauge dims with the other lights, unfortunately it was a while ago and cant for the life of me remember what colours the wires were. There is a write up on vwvortex that had working pictures last time I checked. My gauge only has two wires though (power and ground) I don't see why you would need a third wire. And I don't think it matter whether you tap into the fpr or dv lines as they both are hooked up to the manifold, i hooked my gauge up to each and there was no difference

cheers ok ill try it out, i did see the vortex write up but it had nothing about wiring it up, i found a youtube video for mk5 which could be hella useful for mk5 owners but not for me. also found a detailed one for a tdi too, but no help there either. you remember where you grounded it? also if i go with the dv, its the line coming out the top of it yes? jus want to make sure.
thanks for the quick reply

white is to switchable power - try something easy to get to like cigarette lighter power
black to ground - any is fine
orange to instruments - go from the dimmer switch

It would probably work with just orange and black wired

Switchable power (white) could be the needle light (so it's always on) and dimmed (orange) for the dial

It's a three wire gauge because its electronic not mechanical. The ground needs to be well earthed. Either directly to an unpainted part of the chassis or soldered to ground wiring.

The constant power needs accessories power, you can work this out with a light tester or multi tester. You should have no power on the cable, until you turn on the key to acc. and the orange is for the face of the gauge. As others have pointed out, is easiest to go off the dimmer switch, which is right near your gauge .