Wait until your baby hits their first birthday or sits confidently on their own...

https://telegra.ph/Can-Two-Kids-Ride-on-One-Bike-with-Seats-Everything-You-Need-to-Know-05-10

Wait until your baby hits their first birthday or sits confidently on their own before you ride together. Your little co-pilot needs strong neck muscles to hold their head up in a helmet. Front-mounted seats offer a great view and keep them close