Product Attributes are pieces of data that can add more technical information to your product and help you to refine your catalog while browsing/searching. It works in exactly the same way as product Categories. For example, you can add extra product data like 'Color','Size' or 'Brand' to your products.
Setting up attributes themselves uses an interface you will be familiar with. It’s recommended that you set up any Attribute you will be using over and over in this way. Navigate to Products > Attributes and you will be presented with the following screen:
Here you can quickly and easily add attributes. After adding, the attribute may display without 'Attribute Name'. Then edit the attribute to enter the 'Attribute Name' and click 'save' to update.
Here it is an example of adding Brand Attribute, likewise you can add Color and Size Attributes.
Here you can use attribute for Brands with terms like : Acer, Apple, Asus, Canon, Dell, Google etc,.
Here you can use attribute for Colors with terms like : Black, Blue, Green, Red, Yellow etc.,
Here you can use attribute for Size with terms like : Large, Medium, Small etc.,
To enable brand carousel in home page, please follow these steps
Here is the screenshot for your reference
Here is the video to setup the product attributes