How to get backgrounds on myspace?

how do you get backgrounds what is a HTML coding or CSS?

You get backgrounds by getting the HTML code of the background you want, then you place the HTML code in any one of the boxes when you edit your profile. You can get tons and tons of HTML background codes for MySpace, just search google. You don't have to understand the code, just copy and paste it.
Here is some information about HTML coding and CSS (from Wikipedia)...

HTML:
HTML, an initialism of HyperText Markup Language, is the predominant markup language for web pages. It provides a means to describe the structure of text-based information in a document — by denoting certain text as links, headings, paragraphs, lists, and so on — and to supplement that text with interactive forms, embedded images, and other objects. HTML is written in the form of tags, surrounded by angle brackets. HTML can also describe, to some degree, the appearance and semantics of a document, and can include embedded scripting language code (such as JavaScript) which can affect the behavior of web browsers and other HTML processors.

CSS:
In web development, Cascading Style Sheets (CSS) is a stylesheet language used to describe the presentation of a document written in a markup language. Its most common application is to style web pages written in HTML and XHTML, but the language can be applied to any kind of XML document, including SVG and XUL.

Just google myspace layouts and when you find one you like, they'll give you a really long and confusing code, just copy and paste this code into your about me and you should be set for your background and such.