How do you a fully functional catalog in muse. The kind that you have click and add items to a shopping cart and checkout at the end of the experience. I have taken on a client who sales dress apparel and while I can build him a website, I do not know how to build a catalog, where his customers can select multiple items and checkout.
In Muse is impossible to build catalog (functional part). You can make only a prototype.
For full-featured catalog, you can use a third-party widgets such as Ecwid.
But I would recommend you do not do it in Muse. Take a look at Joomla+Joomshoping, Wordpress+WooCommerce, Openсart.