Okay little one, let me try to explain this to you in a way that you can understand. So, there was a group of people in Ireland called the Provisional IRA who wanted Ireland to be a united country and not divided into two parts. They did some things that weren't very nice to try and make this happen, and one of the things they did was use cars and vans to move around quickly and carry out their plans.
Now, because the police were looking for them and trying to stop them, the Provos (that's what some people called the Provisional IRA) had to be really sneaky and creative with their vehicles. They took regular cars and vans and turned them into what they called "improvised tactical vehicles" or ITV for short. This means they made changes to the vehicles to make them better suited for their purposes.
They might put a big metal grille on the front to ram through barriers, or they might add extra seats inside to hold more people. Sometimes they would put armor on the sides of the vehicle to protect themselves from bullets. They even added metal plates under the floorboards to protect against bombs.
These ITV's were used for all sorts of things, like sneaking around to deliver weapons or explosives, or driving through checkpoints to escape from the police. They weren't very safe though, and sometimes the Provos themselves ended up getting hurt or killed because they didn't have seatbelts or other safety features in their improvised vehicles.
Overall, the Provisional IRA used improvised tactical vehicles to carry out their plans and try to achieve their goals. While their methods were often dangerous and illegal, they show us that sometimes people will do whatever they can to fight for what they believe in.