Click 'Edit my site' to ensure you are in edit mode. In the SiteMaker toolbar, click on the 'Insert' –> 'New page'. This will load the 'Pages' panel. Once the panel has loaded it will display the current pages you have in your site. You can also use the 'Pages' icon on the toolbar.
Click the 'Add a new page' button to add a new page. You will then have a choice of different types of pages to add. These are just starting points and all can be changed to suit your needs.
You will then be asked to name the page and set its visibility (e.g. you can keep it hidden - it doesn't appear in the menu - until you're ready for your users to see it).
You have a choice of adding the new page before the page you are on, after the page you are on, or to the end of the list. However, you can still move them anywhere in your page order by dragging them up or down by the drag handle. Once the page has been added (using 'Finish' and then the 'Apply' button) you can click on it in the menu and begin to make changes.
*The 'Link' page (not to be confused with the 'Links' page which is a page full of links) is slightly different from the others in that it doesn't actually create a page in your site. It creates a menu item which either links out (off-site) to another web page or to an email address.