Posting is light because we’re doing things around the house this weekend. We just replaced the bedroom door (to the outside), and I’m replacing the threshold as well. The thing has an aluminum channel into which a rubber seal fits, after mounting it with screws. But you can’t put the screws in with the seal in place, and once it’s mounted, you can’t slide the seal into the channel (as the instructions say) because the ends are butted up against the door frame. All I can think to do is to shorten it so I have some clearance for inserting the seal, but then the ends won’t have channel, just seal.

[Update a while later]

OK, I figured it out. If I pinch the bottom flat part and bend it upward, I can squeeze the sides into the flange. I still don’t understand why the instructions say to “slide” it in, though.