I wish to add submenus to some of my navigation buttons so that one click will open the page and then offer say 3 more without these three pages appearing on the navigation buttons
There is only one navigation level. You can add sites, but no subsites. But you can fake your structure. Add "hidden" sites (sites which will not appear in the navigation) and link to this sites. Here you can add nes navigation objects and so on... I will write a workshop about the Website Maker soon.