Rearranging theme

I’ve been given the task of rearranging the appearance of a customized theme at https://ad-lines.applinex.com such that the logo should appear below the menu bar and on the menu bar that some items should appear over to the right. I can’t seem to for the like of things move things around like I would with a html static page in Dreamweaver. Please advise as I’m at least familiar with opening the site in Dreamweaver at least and it at least seems to guide me to some CSS pages at least.