That's it really. I've never had a problem before, they've all just taken to it with a few treats and a bit of pushing through and encouragement. SmallCat is really not getting the hang of it, despite having been using it taped open for ages (and having resorted to buying a pack of Dreamies for bribery). She's not particularly food focused, and I reckon used to go in and out windows wherever she was before (rescue cat). It's getting a bit chilly for a taped up catflap and open windows!