The rear seats in the Toyota Yaris fold down to create plenty of packing space.
To lower the seats, pull up on the latch between the head rest and the door. There is a lock on both sides of the seat as it lowers in 2 parts.
If you need to add a child seat, the anchor points are on the back of the rear seats. Simply reach over the baby seat with the strap and clip into the anchor. Use your preferred seat's instructions for installation details.