1. First you must open the file in a text editor. File type becomes an issue here. Your text editor is programmed to save its files in the .txt format and with the .txt extension. However, your browser is programmed to open .htm or .html files. That means that when you save your file from inside the text editor, you must be very careful to add .htm after the file name.
   
2. Add or make your changes to the HTML code.
   
3. Save the changes you made to the file. Be sure that the file saves with the .htm file extensions. (This is the step that seems to be missed the most.)
   
4. If your browser isn't open, open it now. If you haven't opened the page you are working on, go to File -> Open and find the HTML file you changed.
   
   If your browser was already open, go to your browser and Refresh (Reload.) Then the browser will go get the new information that has been added to the file on the hard drive.
   
5. Do Steps 2 - 4 until you are finished with your changes.

It's best to make small changes and check them. That way if you make mistakes in the code, it's easier to find out where the mistakes are.