How to create efficient site navigation with pure html?

This seems like an obvious question here but I’m building a basic website with bootstrap and I need to create multiple pages. I’ve created multi-page sites in the past using various frameworks, but I’m actually not quite sure how to accomplish the same goal efficiently with html alone. I currently have my navigation setup similar to this example.

This is all good in terms of creating multiple pages, but I’m concerned about having to reload everything in my headers over and over again and how much this will slow things down. I’m also thinking that having the filename of each page displayed in the URL is likely not a best practice.