Adding page to the Sunshine menu

I need to create a help page to instruct those of my clients who struggle with the concept of adding images to a package. I don’t need the new help page to be integrated with the galleries or cart but it must appear as a menu item (alongside checkout, account, logout, etc).
How would I do that?
Alternatively, can I have a link to a page appear alongside the “share gallery” and “packages” link in the header?

The page I need help with: [log in to see the link]