How about you start here: . It's a simple vector adder.
Then, decide on what code you want to run on the epiphany and what goes on the host. Then, how you are going to split up your work (i.e. what core gets what part of the job), and that will give you the data structure that you'll need to communicate between the host and epiphany.
Liberal use of host_printf() when things don't work plus grim determination will get you home.