YOU SAID:

me nan don't know how to use her phone

INTO JAPANESE

私nanは彼女の電話の使い方がわからない

BACK INTO ENGLISH

I nan do not know how to use her phone

INTO JAPANESE

私のナンは彼女の電話の使い方がわからない

BACK INTO ENGLISH

My nan doesn't know how to use her phone

INTO JAPANESE

私のnanは彼女の電話の使い方を知らない

BACK INTO ENGLISH

My nan doesn't know how to use her phone