Menus versus pages – navigation

ok, I’m almost ashamed to post this as it shows how HOPELESS I am, but I’m not usually a ludite, but I’m really struggling here folks so need some help please!

I’m mired down because I want to set up navigation (menu I assume)
Under that menu I want to have various posts appear in various categories.

But when I enter in menu items, it’s the pages that seem to be sitting up in what I wanted my nav (menu?) to be…. Should I just post and categorise?

I’m using Blix but will switch if that’s causing a problem. I feel so silly that I’m not working this out by myself and I’ve searched to try and find resolution here.

simple put… I want a few menu items (ok, 9, is that too many?). Under those pages I want the relevant posts, and in some cases static pages (2 static pages)

I’m hoping my sanity can be saved by some help here!