Hi Chicaguapa, i have copied the following and listed the website at the very bottom.
Hope it helps, sorry can't help re se-up grant query.
Booster seat
Group 2 for children weighing 15 - 25 kgs (33 - 55 lbs) roughly 4 to 6 years.
They can be used in the front or rear of the car, but it is safer to put them in the rear, especially if there is a passenger airbag in the front.
Some Booster seats are designed to be converted into a booster cushion by detaching the back rest
Booster Cushion
Group 3: for children weighing 22 - 36 kgs (48 - 79 lbs) roughly from 6 - 11 years.
They can be used in the front or rear of the car, but it is safer to put them in the rear, especially if there is a passenger airbag in the front.
Booster seats and booster cushions do not have an integral harness to hold the child in place. The adult seat belt goes around the child and the seat. So it is important that the seat belt is correctly adjusted. The basic points to note are:
the belt should be worn as tight as possible
the lap belt should go over the pelvic region, not the stomach
the diagonal strap should rest over the shoulder, not the neck
copied from here