I believe you have already ready the previous post about setting up the environment. if not do it here! <PSYCHOPY APP DEVELOPMENT IN PYTHON USING ECLIPSE AND PYDEV>
So, now you are for sure ready with the environment and already created your first application on python. But psychoPy? yes, its not a big deal, you are 80% complete from creating an application in psychoPy already.
These following steps hit the rest 20%.
Set up the interpreter to be psychoPy. This enables you to use psychoPY API.