1. Click File
2. Hover over New
3. Choose Page
4. A Dialog box opens, choose CSS from the Middle Column
5. Click OK
6. Click the Save icon and Name the Style sheet something like "main.css" or "mainstyles.css".
Open the index.html web page in the main editing window. Now look for your style sheet in the Folder List and click and drag the style sheet and drop it on top of the web page. Click the save icon, and there ya have it!