Alright kiddo, let me explain player versus environment (PVE) to you. So you know how when you play a video game, sometimes you have to fight against other players? That's called player versus player (PVP). But with PVE, you're not fighting against other players, you're fighting against the game itself.
In PVE games, you usually have a character that you control, let's say a hero. This hero has to complete different tasks or missions and face different enemies who are controlled by the game. These enemies can be monsters, robots, or even other creatures depending on the game you're playing. Sometimes the game will give you a specific goal to accomplish, like rescuing a princess, defeating a big monster or finding an important item. You have to use your hero's skills, weapons, and abilities to defeat these obstacles and complete the mission.
PVE games can be very fun because they allow you to explore different worlds, learn new skills, and defeat different challenges. They can also be played alone or with other players who will help you complete missions together. So, that's PVE in a nutshell, it's all about fighting against the game with your hero to complete missions and defeat enemies. I hope that makes sense, kiddo!