Please read below step to add banner slider in Magento 2
Install extension and enable from configuration.
You can create slider from Content --> Banner slider --> Add new slider.
You can set slider configuration as per your requirement.
Then you want to create slide and assign this slide to particular slider.
Then you can copy slider code and add code in any cms pages(Content --> Pages, Content --> Block) where you want to display slider.
Suppose you add code in home page then your slider visible in home page of store
Learn more here https://www.mageants.com/responsive-banner-slider-extension-for-magento-2.html