Okay kiddo, have you ever played with a remote-controlled car or airplane? You know how you have this little controller in your hand that helps you make the toy move? Well, that's a bit like what a control line is for some toys, but instead of using a remote, there are physical cords attached to the toy that you hold onto.
Let's say you have a toy airplane with control lines. The control lines are two thin strings that are connected on one end to the wing on each side of the plane. On the other end, you hold onto them with your hands.
When you move your hands, the control lines move too, and because they are attached to the wings, they make the airplane turn or go up or down. So, if you want the airplane to go up, you pull up on the control lines, and if you want it to turn right, you move the control lines to the right.
It's kind of fun to have control lines because you can make the toy do really cool tricks and stunts in the air. But, you have to be careful because you have to stay in one spot while you're holding onto the control lines or else the toy might crash into something, and that wouldn't be good.
That's pretty much it, kiddo! Control lines are like strings that you hold onto to make a toy move, and they're pretty neat to play with.