The EOArrow consists of solving the arrow while orienting all of the edges. It is very similar to the EOLine in ZZ, so if you know ZZ it should be pretty easy. This differs from the pEOArrow because when you are done with HKF2L the edges will all be oriented. An intermediate approach would be orienting all of the edges, and then solving the arrow. An advanced way would be to solve the arrow and orient the edges simultaneously. The concept of EO is tricky to grasp at first, so I would recommend watching ZZ tutorial videos on YouTube.