Imagine you have a toy car that goes around your room. Now imagine that instead of toys, we have big ships that can float on water. But some of these ships are not just for carrying people or things around, they have a special job- to place mines in the water.
Mines are like little bombs that stay hidden in the water and explode when something touches them, like a boat or a submarine. A minelayer ship is a special kind of ship that has lots of different compartments where they keep these mines.
To lay a mine, the minelayer scoots along the water and, using special equipment, it drops the mines out of the back of the ship into the water, like a trail of breadcrumbs. After they have laid their mines, they move away quickly and don't look back as the mines work their magic.
Minelayer ships can be very important in times of war or conflict because they can help keep enemies away by filling the water with dangerous surprises. But because they can also be dangerous for regular boats and ships, it's important that they're used carefully and responsibly.