How do I identify a step up or step down transformer?
A transformer can be both a step up or step down, it just depends on the turns ration and what you consider to be the primary and secondary windings. 

What you can do is use a function generator to excite a set of windings and then measure the open circuit voltage on the others windings. This can allow you to estimate the turns ratio and see if transformer will work in your application. 

This can give you a better description of how a transformer works and how to do the calculations.