both 새 and 새로운 mean almost same, meaning of NEW. for ex, new book = 새책 or 새로운 책. 새 and 새로운 is adj., located in the front of Noun. But, exactly, this is a new phone = 이것은 새 전화기입니다.(I buy a new phone) or 이것은 새로운 전화시입니다(I buy a new phone (coz mine is too old) or I buy a up-to-date phone that is of recent invention.