Wiring Advice Please

[LambethBoy]

Have one of these units(see pic) would like some advice on the best place to hook it up to?
also would be great if the more technical minded of you could point out best wire gauges etc.
Thanks guys

 

[Dellmassive]

Have a look here )))

Installing 12v Socket /s - How Its Done -

.

 

[LambethBoy]

Have a look here )))

Installing 12v Socket /s - How Its Done -

.

Nice @Dellmassive