Caravan electrics help please

[terranosaurusdoug]

I have started an attempt to educate myself on electrics, specifically 12v, however my brain is refusing to process the information and just seizes up I think I may have this one figured though but would like advice and opinions please

I took my old porch light off the caravan as I have another one I want to fit, I didn't realise the new one had no switch and that's when my heart sank. I've bought a switch which I will mount inside on the opposite side of the wall to the light but I'm not sure about these wires.....
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I thought at first there was three different wires but now I believe the pink one is positive and the other two are in fact the same wire (one coming and one going) which is negative.

The switch I have has three connections and the new light has two wires. SO... I reckon I need the pink positive and the white and orange negatives to my new switch, which will leave a third connection on the switch, this will be a positive to the new light and the negative from the light will go back to the switch and into the same connection as the white and orange negatives. I apologise if that lot is hard to follow or makes no sense, please help