Okay kiddo, so you know when you take a bath or go swimming, you get completely wet, right? Well, immersion baptism is kinda like that. It's a special way that some religions or churches baptize people.
So, when someone wants to get baptized, they go to a special place, often a pool or a lake, where the water is really deep. Then, they put on special clothes called a white robe, which is kinda like a gown, and go into the water.
Once they're in the water, the person who is going to baptize them, usually a priest or a pastor, will say some special prayers to bless them. Then, they will take them and put them under the water!
But don't worry, they don't stay under the water for very long, just a few seconds. It's like going swimming and holding your breath for a bit. When they come up out of the water, everyone cheers and claps because it's a really special moment.
The reason some people choose to do immersion baptism instead of just pouring some water over their head, like in other types of baptisms, is because they believe it symbolizes them being washed clean of their sins and starting a new life with God.
So that's what immersion baptism is all about, kinda like taking a really special bath in a big pool of water to show that you love God and want to start a new life with him.