Okay, so think of it like this; when you play a game with your friends, you might have a leader, right? The leader is the one who makes the rules and helps everyone know what to do. In the church, the bishop is like the leader.
Now, the historical episcopate is just a fancy way of saying that the bishop has been around for a really, really long time. We can trace the history of bishops all the way back to when Jesus was alive, and he picked Peter to be the first bishop of the church.
Ever since then, bishops have been like the important grown-ups of the church. They help make the rules and they help people follow God's teachings. And because they've been around for so long, they have a lot of knowledge and experience that helps them guide the church.
So when we talk about the historical episcopate, we're really just saying that the church has had bishops for a really, really long time, and that they're important for helping us understand God's love and how to follow him.