Any Odoo users out there who can help with some web page design tweaks?

I've watched their tutorials and asked questions on the forum without success; looks like I may have to use the HTML/CSS editor, but can't seem to figure out how it works exactly.

For the moment, I'm just trying to move text around on the header and make some other associated tweaks; I can go into more detail if this sounds like it might be up your alley (ok, that sounds kind of weird, but I guess you know what I mean . . . )

Would be much obliged for any help!