Adding pages is easy in Shift. The key point to remember, is when you click on 'add page' it will add as a sub page of the page you're on. For example, if you navigate to your about us page, and click 'add page', it will add a sub-page of about us, and appear in your dropdown menu. If you want your new page to be a standalone page, with no links to it from your menu system, just click the 'add page' button while you're on the homepage.
The main page categories up the top are set. These were programmed in to match what was on your design concept.
When you click 'add page', simply choose a page type, and type in the name of your page. An 'alias' will automatically be created for you – the alias is basically your URL, or web address, of the page, that will appear after your domain.
If you want your page to go live to the public at a certain date or time, you can even put this in here. Most people just leave this as the default however.
Once you've selected the page type and typed in a name, your page properties will appear. At the bottom of your properties, you'll notice some tickboxes. You can exclude your page from being listed on the dropdown menu and page list by ticking 'Exclude from Nav'. You can prevent your page from being listed by the search engines by ticking 'Exclude from Search Index' and 'Exclude from Sitemap'. Most people just leave these boxes alone however.
The rest of these page properties are for search engine optimisation, or SEO. At any point, you can edit your page properties by clicking the 'properties' link on the toolbar. If you'd like a full tutorial on SEO properties, just click the 'page help' link on this page.