Range Rover Tail light Change

[ryanl12]

Hey, I just got a 2003 range rover. The 2003 range rover has tail lights like this

I would rather have tail lights that look like this. These tailights come standard on the supercharged range rovers.

Now, I have researched about where to get the tail lights but, I just don't know how to install them. I just don't want to buy the lights through the internet and not be able to put them on my car. Also, I want to avoid taking this to the dealership because I know it would be really expensive.
The site im looking at buying them from is http://www.xtremerovers.com/range-rover-supercharged-tail-lamps-xfb500351lpo-xfb500341lpo-p-81.html

Just let me know if you have any information on how to install them.

Thanks, Ryan