Complex sentence: Naksh is Naitik & Akshara's son, Gayu, is Nikhil-Rashmi's daughter, (Sameer's stepdaughter) after Rashmi & Sameer's death, Naitik & Akshata adopted Gayu.
Split into simpler sentences: Naksh is Naitik & Akshara's son, Gayu, is Nikhil-Rashmi's daughter (Sameer's stepdaughter). After Rashmi & Sameer's death, Naitik & Akshata adopted Gayu.