"We bought this just to see how it went over in our cage, it was in very good shape, no dust, sawdust, problems, etc. It doesn't come with anything to attach it to the cage but some minor improv fixed that problem. We attached it inside in the very top part of our weird cage by cutting an opening big enough into the top most cage , a couple improvised drill holes into the wood and some wire. At the start they would sit on the perch we have a couple inches away from it, kind of looking it at and then looking at us like we are insane. Our next step was put some millet in the box, a little bit hanging out and a crack stick(lol, sorry those are the honey seed sticks to our birds) just down from where the platform is.
We came home one day and went to the keets' cage with some new treats and only counted 7 keets well after initial freakout we went to open the cage door and the sound of that produced a yellow head from the box. Needless to say that is her nest box now, and no one is allowed near it, they can get as far as the perch down from it but any closer and the world is over.
I personally recommend putting the next box outside of the cage or improvising like us and attaching it medium-high in the cage. These are not ground birds and they feel safer up then they do on the ground. Improvise on attaching it, put some of their favorite treats near it or in it and soon hopefully you'll be having that minor freakout."