It's easy when you know how and a zip inserted into a purse or jacket can work so much more effectively than buttons. Zips provide a neat closure and don't detract from the pattern and yarn work. The video explains the principle really well and you can follow along. It is not hard but you just need to be methodical and patient as you start it off. If you specifically want to see how to put a zip into a crochet purse there is a really good video in Portuguese. If you don't speak the language it doesn't matter because the visual aspect of the video is done extremely well. Once you understand how it is done you will work out your own way of doing it.