Thanks for your message Moodles!
I had tried the 'Add New' prior to posting this message and when it didn't work, I searched under the 'help' option. Here's what I got:
"Pages are similar to to Posts in that they have a title, body text, and associated metadata, but they are different in that they are not part of the chronological blog stream, kind of like permanent posts. Pages are not categorized or tagged, but can have a hierarchy. You can nest Pages under other Pages by making one the “Parent” of the other, creating a group of Pages.
Managing Pages is very similar to managing Posts, and the screens can be customized in the same way.
You can also perform the same types of actions, including narrowing the list by using the filters, acting on a Page using the action links that appear when you hover over a row, or using the Bulk Actions menu to edit the metadata for multiple Pages at once."
So technically, it's telling me I can only post 'pages' in a similar way to a post - not a new 'tab' option, which is what I want. I did try it out - just to make sure, and it is in fact coming up like a blog post...
Is this a function of the theme I chose, or is this standard to WP in general?