Imagine you are riding your bike (if you have one, but if you do not, just follow along) on the sidewalk and you fall off and you get a cut and you bleed. Later a scab forms over your cut. After a few days your scab falls off and your cut is healed. What happened under the scab that healed your cut?
Your skin is made up of skin cells. When you get a cut, skin cells fall off and you bleed. When you bleed a scab forms over your cut to stop the bleeding while your body gets to work to heal your cut. Here is how it does that.
When a scab forms over your cut, the skin cells outlining the cut actually multiply. They do this by dividing themselves into two cells. They keep doing this until the cut is completely healed. When the cut is healed the skin cells do not know that the cut is healed, so the brain sends a signal to the skin cells that tells them to stop dividing, and then the scab falls off. And that is how cuts heal.