Greek Accentuation

hi, is it absolutely necessary to learn all the accentuation in Greek? and if so, should I memorize the nominative lexical entry and then apply the rules in the other forms of each word? I mean is that the right way to learn?

Eventually, yes, but you can definitely learn the system little by little. Are you learning on your own or do you have a teacher? What textbook are you using? Welcome to Textkit!