To make an HTML file using Mac TextEdit:

1. Open TextEdit (I find it easiest to go to the spotlight icon in the upper right and type "textedit")

2. Select: TextEdit > Preferences

3. Under "New Document" make sure that "Plain text" is selected, not "Rich text"

4. Select: "Open and Save" in preferences

5. Make sure that "Ignore rich text commands in HTML files" is checked

6. Close any open TextEdit documents

7. Create a new document by selecting: File > New

NOTE: If the window you're entering text into has the formatting toolbar (with a ruler for margins and font selection tools), you have not done this correctly.

To Save this file:

1. Select File > Save

2. Save as "index.html" Do not adjust the encoding, just replace the current "untitled.txt" with "index.html"

3. When prompted to use ".txt" or ".html", choose ".html"