Menus are a great way to organise and help viewers navigate easily around your website.
When you create a page and a post you will need to organise them accordingly.
On the left hand side bar select appearance and choose menus. If you want a page to appear on your menu bar you need to add the page to your menu by selecting from your posts and pages on the right panel. If you want a page to appear as the first topic on your menu bar you need to move the box fully to the left. If you want a post to appear under the page in your menu then the box needs to be moved slightly to the left so it looks like ouse made a indent.
This is a example of my menu bar. As you can see all my main pages are seen first on the menu bar, until you hover over the page then it provides a drop down bar where you can choose the relevant post.
However, the top level domain page had two bits of information that I felt needed 2 pages so I created two sub menus under top level domain.