Group 0+/1 car seats will last your baby from birth to around four years old. Your baby will initially travel in the seat rearward facing and you can change the seat to face forwards. Some seats allow this from 9kg (approximately nine months) but it is not recommend you turn your baby forward-facing too soon.
You should leave your baby in a rear-facing child car seat until they are least 15 months old. Many Group 0+/1 car seats let your child to travel rearward facing until up to four years old. Unlike a baby car seat (Group 0+), a Group 0+/1 car seat will stay fixed in your vehicle. You won't be able to take it out and pop it onto a travel system chassis. They are also larger than a Group 0+ car seat this type of seat may take up more space in your car.