[pugbod]

Does it mean put the red to the yellow and yellow to red or swap pins round

thats exactly what you need to do but dont forget you wont be able to use the steering wheel buttons if you have them.

 

[pugbod]

the wires should have connectors so you should be able to simply switch them round pin wise and no need to cut into any other wires.

red to yellow and yellow to red

 

[pugbod]

simplest way without damaging your internal wiring is to connect the red to a permanent live and yellow to a switched live like ignition,

when using the original wiring your breaking into the cars system and that's not good due to later cars having CAN bus so unless you buy the accessory wiring made up it wont work through you inboard system like the steering wheel controls,

aftermarket radios have the permanent live = red
switched live = orange/yellow
so you have to reverse them if your using the system wiring.