Okay, it’s actually labeled “2”. It looks like I took two screw off the bottom. Be careful when you open this up, there is a spring that can fly out.
There is also a c-clip, which probably holds the whole assembly in place. I’m guessing you need to open the main body of the router to get the piece off. You might have to remove the clip, which is easy enough.
Sorry I don’t have better detail – I did this as soon as I got it and haven’t thought of it since. I will say that it was very easy, and you shouldn’t worry about screwing anything up. Just take your time. The piece you’re removing comes off without damage, so you can save it in case you ever want to reinstall it.