How to setup Bootstrap 4 Carousel with Craft CMS 3?
A matrix field for an image carousel needs only a single asset field, one that will accept more than one image. In my experience there is rarely a requirement for anything more. 99% of carousels I have implemented look like this: 



If you wanted to add text to accompany each slide you could add a text field directly to the image asset and then display that with each carousel slide: