How do I get some pages on menu bar and some on sidebar

I am a complete newbie here, though I do have experience programming but little experience with HTML, CSS, PHP. I am hoping for pointers were to look to get to where I want to go

I am building a site for our organization that teaches safe boating classes. I have pages for a course catalog and one for a course schedule, club history, about also pages for each of upcoming events.

I want to split these so only pages about upcoming events go to the sidebar and the rest go to the menu bar. I’d also like to have drop down menus in the menu bar so for instance there is an about button that would have sub item pages for club history, board member descriptions, and contact detail.

So that’s really 2 issues, creating drop down menus with links to pages and directing different pages to different places. Is there a place in the documentations that addresses these issues?

Thanks for your help.