Theming Exposed Filters

Hello. I need some help figuring this out. I created a view using exposed filters in the form of a search. On the page, it looks scattered. I would like to know how to put everything into a frame, add a background, and change the layout of the rows. I probably need to edit the CSS, but I'm not sure where to do that or what exactly to write. I'm not lazy; if you point me to where I can read about it, I'll gladly do it. I've attached the file.