This worked for me!
And for anyone who has an existing mount already in the ceiling - this model will likely fit. But for me, I had to use the original bracket that came out of the box to actually activate it. These are the steps I took: get the original bracket, twist the unit into place, you should immediately hear the unit activate when you hear a single loud “BEEP”, take the unit out, and now place it onto the existing mount in your ceiling.
Just a heads up in case anyone else runs into this issue!