The mod adds a trebuchet multiblock, to build it you need to craft the base block and place it in the world, a blueprint will appear showing the size and position of the multiblock. After placing it in the right spot, it will ask you for resources, with right click it will takes the resources from your inventory and when it has all the needed resources, it will place the structure.
To fire the trebuchet just click on it in any part. It will use TNT as ammo, if there is any entity in the middle of the trabuchet, it will shoot the entity instead. To reload the trebuchet, just right click again.
This is a small preview of the mod