Ok kiddo, imagine you have a mommy and a daddy, but they decide to get a divorce. Then, your mommy or daddy may find someone new they like a lot and want to get married again. This new person is called a step parent.
When your mommy or daddy gets married to this new person, they become your stepmom or stepdad. They do not replace your real mommy or daddy, but they become a new part of your family.
Sometimes, when your stepmom or stepdad already have kids of their own, those kids become your stepbrothers and stepsisters. This means you have a new family with more brothers and sisters!
It can be tough to adjust to changes, but it's important to remember that your stepfamily is just a bigger family that has more people to love you. It can be a lot of fun to have new siblings and to get to know your stepmom or stepdad, and they might even become some of your best friends!