To say “I don’t know anything about it” you say “Je n’en sais rien” but in spoken French you hear most of the time “J’en sais rien”. Listen to the 2 ways of saying it and try to imitate my pronunciation as closely as you can.
Note: In casual speech, we often don’t pronounce “ne” in a negative sentence.
Ex: Je ne mange pas is the grammatically correct form but in spoken French you often hear “Je mange pas” which is grammatically incorrect