LaTeX is a free software for making scientific, technical documents and thesis. It uses the TeX typesetting program for formatting its output, and is itself written in the TeX macro language.
If you’ve never used LaTeX before: you can install a program that will allow you to create LaTeX documents on your computer.
For Mac: Download the full MacTeX package from http://ftp.uniroma2.it/TeX/systems/mac/mactex/MacTeX.pkg . Once you have downloaded the file, open it and you will be guided through the installation. This will place TeXShop in the folder Applications/TeX/.
For Windows: Download MiKTeX from http://miktex.org/download . Once installed, navigate to the MikTeX folder under programs and run TexWorks
You need programming experience. Once you have the basics, you can choose what you want to learn how to make using LaTeX.