Wait until your baby is one year old and sits up unassisted. They must hold...

https://smoothdecorator.com/cold-weather-biking-what-should-your-baby-wear-in-a-bike-seat/

Wait until your baby is one year old and sits up unassisted. They must hold their head steady under the weight of a helmet. Pick front seats for engagement, rear seats for better balance, or trailers for napping