Menu system and pages.

Good evening everyone. Im trying to setup a website with additional menus outside of the ones that come with the apps. So i would like to add a menu to the LHS with some sub menus. So for example the menu system would have cast, then a sub menu with the list of cast. this may be a simple process but im struggling with it at the moment. If i can work out how to put the menu system there with sub menus then i can create the other sub menus. Im also struggling with the pages. Ive been given a website that is html and im finding pages dont like a straight copy and paste of the html from the old website. Any help would be much appreciated. so to recap i want to add a menu system to the left hand side that appears on all pages. I want to add sub menus that load individual pages but keep the menus and top menus loading as well. The pages will need to be created with simple text and pictures. Is there an easy way to do this? The website im trying to port over to UNA is onthebusesefanclub.com