Explaining Adoption to kids

In our family there's a lot of kids. Like a lot, I think there's close to 40 at this points. As you can imagine my nieces and nephews had a lot of questions about our kids. Their adoption is a little different than the other adoptions in our family, in most of the adoptions we knew there was a child coming and months, or even years in one case, so the kids were a little prepared. For our kids however, they just kind of appeared one day and we were telling the other kids that they were their new cousins like how confusing is that? One moment were just a couple without kids and within 15 minutes we had four kids, how do explain that to a four year old(most of our nieces and nephews are four). We decided to let their parents do it-I know we're wimps, but I will be keeping my sisters way of explaining it. She sat down her kids and had them watch Annie, when the movie was over she explained that Annie needed a family and there were tons of kids just like her out there who need families as well. After explaining that she talked about how some of her kids are adopted and asked them how we should help kids who are adopted. They all had different ideas, but the main idea of giving them families was the same. Once she had them giving those ideas she told them we were going to be taking care of some kids until their parents can do it and if they couldn't we would end up being their parents forever. They were okay with the idea and welcomed our kids with open arms and even shared their toys! If we had waited a year to adopt there would have been an even easier way to explain it. The Disney show Doc McStuffins actually just did a whole segment on adoption and all of my nieces and nephews, even the 11 and 9 year old, watched it. It explained adoption perfectly for preschool aged kids to understand. I highly suggest if you're adopting and have any kids in your family to have them watch that, it will answer a lot of questions and will also open the doors of communication for you. Just remember kids ask questions, they don't hold back and they want to know everything even if you don't know the answer. Please try to answer them though, if you don't answer the questions they may feel unloved or like they're being replaced.