how to open daisy text formatted books on MacBook

hello everyone
I have latest MacBook air with the latest operating system operating system
I have recently purchased MacBook here and I am a voice-over user user
I want to open book share books on my MacBook
bookshelf books are Daisy formatted books
but I’m not able to open Daisy text formatted books on my MacBook
I have tried read here application
but Apple is not installing it because it is from an unidentified developer
moreover it is extremely costly
I have a huge collection of daisy text formatted books which I want to open read
how can I open book share Daisy text fermented books on MacBook kindly help
I know I can download EPUB format from bookshelves and open it with Viber
but as I told I have a huge collection of daisy text formatted books I want to open heart Daisy text formatted books and I want to open that
please help