If you drag them into a carousel, they go in as a single entry. You need to create a group first that will have your pic & descriptive data, which are linked to respective fields from your excel file.
Then add the excel file to your scene, and drag your group over the the excel section on the left (the heading in the scene structure that says Rows). By default it will display in an asset grid. Change the asset grid to a carousel.
As Melvyn explained, when you drag and drop an excel from windwos to Composer, it will automatically create (by default) an Asset Grid collection with the elements of excel within.
You should Drag and Drop the excel on the scene not in the Carousel then change the Asset Grid into a Carousel collection. Please see the image below for more details: