To create attractive web applications, it is necessary to apply styling. You have taken a previous course on HTML and CSS. Bootstrap is a commonly used library of CSS styles that ease the creation of attractive applications. Optionally, you may want to view this video.
Please review this site: https://www.w3schools.com/bootstrap5/ . It gives a tutorial on the use of Bootstrap. Also, refer to this site: https://getbootstrap.com/ . It includes complete documentation on the use of Bootstrap.