Writing documents/papers in LaTeX is an entirely different story (I barely know how to write one, even though I'm familiar with math typeset). But for you, you'll probably also be writing only math expressions for now.

Basically, to wrap expressions in LaTeX, use the [TEX] tags, which can be done by going to "Go Advanced" and then clicking on the . Or you could just type them in.

Formatting is a little tricky but typesetting math is fairly easy. Usually you use a \ in front of a command (e.g. \sqrt, \mod, \epsilon, \frac, etc.). Use curly braces to separate "arguments" of a function, for example, if you want the square root of 3, you would type \sqrt{3}. A fraction, such as , is denoted \frac{x}{y}.

If you have a subscript or superscript (such as or ), you would write a_n or a^n. However, for subscripts or superscripts longer than one character, you must use curly braces. For example, a_10 shows while a_{10} shows . Sums, products, and integrals are also tricky, but with a little practice you can input expressions such as or .

A (nearly) complete list of LaTeX symbols and commands can be found here: LaTeX:Symbols - AoPSWiki