Bootstrap is a powerful front-end framework for faster and easier web development. It includes HTML and CSS based design templates for creating common user interface components like forms, buttons, navigations, dropdowns, alerts, modals, tabs, accordions, carousels, tooltips, and so on. Bootstrap gives you ability to create flexible and responsive web layouts with much less efforts.
Go through this playlist to get the basic understanding of bootstrap.
Follow this short tutorial to create a Carausal by using templates, don't worry as it will be much much easier compared to manually create a caraousal. You need to submit this either as a new webpage aur simply adding it to the existing webpage.
You can always refer to W3Schools: BootStrap 4 Tutorial for more. You can also check these videos: freecodecamp.org ,Code With Harry.