Sometimes teachers require papers with footnotes written according to Turabian or Chicago style. This happens most often in history class, but teachers in other disciplines might call for Turabian style papers, as well.
First of all, it may help to know that there is very little difference between Turabian and Chicago: Turabian style is rooted in the Chicago style of writing. The main difference is that Turabian was developed specifically to provide instruction for writing papers while Chicago includes instruction for writing books.
If you find that you need a temporary guide for writing citations in the Chicago format, you can consult the Chicago Manual of Style Online. You can sign up for a 30-day free trial and start using it right away.
Online style guides are great because they are easy to search. Each time you have a question about a certain aspect of style, simply use the internal search function for a quick example!