Modify page display

I am creating a web page with the theme “Parabola” for an administrative agency and on the main page I see a window that does not remove logo.

I will try to explain myself as much as possible so that they can understand me and be able to help me. At the top I have the logo and below the menu with the submenu perfectly created and working.

Now the problem is that underneath I wanted to put several pictures of the most outstanding services. That I have managed to do and they work.

Now the problem is that underneath I have a window that shows nothing and that if I select an option from the menu, it shows it to me there in the empty window and the images that I have mentioned do not disappear.

Would I know how I could do it or would they know of a topic that suits my needs better than what I have now?

Thank you for your attention.