You just need to pull the entire silver bezel from the dash that surrounds the diffusers, stereo and heat controls. I find it easiest to start at the bottom. If you take the very bottom and press 'up' you can feel it's a little sloppy. Press that up high enough to get your finger behind it and pull it away from the dash. It's easier if you use a small screwdriver or other flat type tool. Maybe start in the center where there is more flexibility. You can't see down there, so you don't need to exercise a ton of caution not to scratch it, but it's still nice to take necessary precautions. Once you have the bottom pulled away from the dash slightly, work your way up. There are two points of contact on both sides of the bezel. One set of them are I believe near the heat controls, or maybe up a little closer to the stereo. Then there are two more near the top. Both sets are in line horizontally with each other. It's nice if you work up both sides together and pull away easily. Use a little caution if you are working in a cold environment. Plastic is brittle in the cold.
The two diffusers come with the bezel. There are two wire connectors attached to the back (if you have 4x4). The larger one is for the 4x4 buttons and one is for the hazard lights. It's a tiny wire at the very top. The 4x4 comes off easily, just locate the squeeze tab and press it in and wiggle the harness out of the socket. The smaller wire has a tab that you need to lift, it's a tiny metal tab and it's on the top of the plug. A small screwdriver works well because you can lift the tab where there is limited finger room, then wiggle it out.
The stereo is held in with three screws, two on the left, one on the right. 7 mm socket is all you need. Carefully pull it out then unplug the antenna and any wire harnesses in the back. Two harnesses if you have SAT, one otherwise.
I think there is a thread on here with pictures but I'm not sure where I have found pictures. Once you get the bottom popped out it should be a breeze. The vents may come out of the bezel, they snap in place. In the event they come out, the sort of hinge back into place. Remove the vent diffusers completely, then insert the top of the diffuser into the bezel lining up the two locking tabs. Once they are aligned you hinge the vent down to engage the two bottom locking tabs. That will make more sense when you see it. To put it back on, plug in the wire harnesses, line up the diffusers in the vents and work your way down pressing the tabs into the locking holes down the edge of the bezel.
Good luck, hope this helps. Let me/us know if there are any more questions.