If I remember correctly, there is a right up on how to do it here somewhere. Short story, You'll have to remove your A-pillar covers and the dash trim(the one with the vents) and then the speaker grille and then you can get to removing that piece. Be careful there's a solar sensor on that panel, make sure you disconnect it before yanking it out of there. After removal you can go to town with it using adhesive foam tapes. Search on Amazon "anti rattle tape". There's also a camper tape at Autozone that I had used and works well too. It's a foam roll with adhesive that's very pliable and easy to work with.
I did this and posted photos if you look through my post history. pulling It apart and padding with felt tape on the underside has solved the rattle for me, I did this almost 2 years ago now and it’s been silent.