Codepen assigning buttons to link my different website pages

Good evening! I have followed Freecodecamp up to the point of making my own portfolio where we have to link buttons to take us to different home page urls within my website. As I am not saving each HTML file as we using CodePen, what do I type in my href tag to direct the user back to home page, or about me etc? I believe the normal way is saving each HTML file into a folder and then mentioning the name of the file in the tag would work but codepen is confusing me as its all built into itself and i cant save individual html files.

Thanks alot,

If I understand correctly, you can have a look here: W3School - a Href attribute