Use the rear rack
Basket, child seat, or panniers, within the 25 kg limit.
The rear rack can take a basket, a child seat, or panniers. Keep the total load at 25 kg or less.
Spread the weight evenly on both sides. Do not cover the lights or reflectors, and make sure no strap can catch in a wheel.
Do not attach a trailer to the rack, and do not modify the rack yourself.