Assuming the Kokkino Chorio you quote as your location is in Chania Nomos I would recommend using George Atsalakis in central Chania, opposite the tax office, as your accountant. If you have a tax number you will need to interact with the Taxisnet on-line tax system and unless you are fluent in Greek to degree standard and have a deep understanding of Greek tax law I would avoid doing that yourself. Let an accountant do it for you.
email atsalak at otenet dot gr
web page http://www.cretanaccountant.gr
If you click on the middle tab, Tax liabilities in Greece for non Greek citizens, there is tons of information.