Did this myself recently and it helps to have some trim removal tools. I bought a set off ebay for £4.
Firstly start at the top nearest the screen and gently pull away, using the trip tool and then fingers. As you work your way down you'll need to move the bottom part back and forth to free from the clips. Then you can pull it out, again be gentle. It's quite straight forward but awkward to describe, there are some videos on youtube you could watch.
I did it to fit a dab aerial and removed some other trim bits and it's easy enough. Good luck with it.