Quoted from killerrobots:
Actually harder to get off than on but here is what I did.
Insert your left side so it is sitting on top of the limit switch and the right side is positioned higher on the ramp. Like this:
Then drag the right end down the ramp surface until you get to the hole and it pops in. I was also pulling the side of the ramp away from the spinner but it doesn't deflect much so this might not help at all. There will be some resistance but mine survived.
Thanks man, ended up forcing it harder than I wanted but it held up!