I am trying to deploy my site but it is showing that "Page Not Found; Looks like you've followed a broken link or entered a URL that doesn't exist on this site." error. How do resolve this, given that I am not using any framework rather just html and css?

Here is the link https://app.netlify.com/sites/infallible-wilson-fde7d3/deploys

Depending on how you built you site, you almost certainly will have to check the paths for your files.

You might also check some of the existing resources that deal with issues such as this: