Not sure what to do? Look at this simple example post and the introduction to MathBin.net posting.
Now that you know the basics of MathBin, you need to get up-to-speed on the basics of LaTeX. Don't be alarmed when you start looking at it, it's really quite simple! Try searching for introductions to LaTeX equations.
We also have a handy LaTeX reference page on this site for you to use.
Visit the forum if you have problems or questions.