This article includes a 2:06 video walkthrough.
Quick answer
Each arm pad is held by four short screws underneath. Two are hidden, so center the pad to see all four. Use the included tool to remove them, and hold the pad steady before the last screw comes out so the grease underneath doesn't get on your cushion. Install the new pad the same way: center it and put the screws back in.
Step by step
Look under the arm pad. You'll see two screws at the front. Slide the pad to center it so all four screws are visible.
Remove the screws with the tool included with your new pad.
Before you take out the last screw, hold the pad with your other hand. There's grease underneath that can get on the cushion if the pad flops over.
Center the new pad and put the four screws back in.
Also called: armrest pad, arm cap, replacing the arm pad, worn arm pad.
Video transcript
Alright. It's time to replace an arm pad, and you've been shipped your new pad and this nice little tool. How does it come off? There are four bolts underneath this, but I want you to take a look. You probably only see two of them, the two up front. Where are the other ones? They're hidden back here. Slide your arm pad back, and it reveals the other two. But I slid it back too far, and now I've covered up the front one. So what you want to do is center it between the two so you can see all four. And now it's time to take it apart. They're not very long screws.
Okay, now the important part. There's grease underneath here to make the parts move, and you don't want your arm pad to flop over while you're taking this off, so the grease on the bottom gets on your cushion. So before you take that last screw out, put your hand on it and control it. Take that last screw out.
Now come on over here. I'm going to pry it open so you can see the grease in here. There's grease on the top, and there's grease right there. You can imagine this flopping down and hitting your white cushion. Yuck. That would be a pain. So now that this is off, you have your new arm pad, and it goes on the exact same way. You just center it and put the screws back in the way they came out. It's that easy.