The UTF 15t 8x8 is a standalone mod without dependencies.

Steps

1. Subscribe to the mod in the Arma Reforger Workshop, or add it to your server's mod list.
2. Start the game and place the vehicle in the Game Master editor, or add the prefab UTF_15t_8x8.et to your scenario.
3. Get in through the doors. The driver sits on the left, two passengers on the right and in the middle.