Header Placement

Hi!

I am new to cc2018.  I can work with the cell sizing and spacing but I don't want my header to sit on top of the first cell.

I want it at least 1/2 inch up.  I have played with the margins but that adjusts the entire document. I can't see where I can adjust the height of the header.  I can do it in Photoshop but I don't want to go page by page through my documents.  Thoughts?