Need Help With Custom Header CSS

Hi every one, I need a little Help with my business website header

I would like the bring the logo down and move pages right next it it (side by side), I already entered a code on the css to move the logo and the description right (it was centered on the original theme) this is what I used:

#header div.logo a img {
margin-left: -620px;
}
#header .blog-title a:hover {
margin-left: -620px;
}
#header p.blog-description {
margin-left: -620px;
}

I know its something easy too doo but I design and I’m still new to programming, so if anyone could help I would very much appreciate it

Regards

Nancy