My Ancestry DNA Experience

I have always wanted to know where my family came from. My family has a weird history...  My mom had a good guess of her family's history but not much from her father's side. She believes she is Irish and Cherokee Indian. My dad had a Russian sounding surname but his family was from Puerto Rico. There was some drama when he was born in the 1930's and his father's side of the family disowned them. I have no clue about his mother's side of the family.