My grandmother, and her sisters did rosaries all the time. The marians at church make them all the time, then hand them out at hospitals and etc.
Why would you need special permission? I would do my research to find out how it is laid out but other than that, if you need one, then there are others who might need one too. There are sites online who have rosary making supplies, or you can use chord. they also have the rosary medals, crucifixes and things you don’t always find locally, but your local religious book store may have access to whatever you need. They might also be a good resource for a book on making what you want to make.
awesome.