GIVE ANSWERS - Νέα Ελληνικά

I just started to learn Greek, I am a beginner. so I downdloaded a Greek modern bible translation. and in John 1:1 says: Εν αρχή ήτο ο Λόγος. so I searched the conjugation of 'to be' and there I found that in imperfect 3rd sg. was 'ήταν'. then what does  'ήτο' mean? in what time is it conjugated. or it is not modern Greek?