Co-sleeping and the bed arrangement?

What do parents do to protect baby from falling off bed? We've been co-sleeping on a floor bed for a while. We've now got a new bed and I just don't know how people do it? We've downsized from super king to double 💀 as I don't want babies sleeping in this bed (ASAP really, another stress in my life aka sleep training 😭). My other half says if our little boy is co-sleeping with me, he won't sleep in the bed. That's fine. How do I make it safe for little one? My little one literally like jumps into different positions in the night, I wake up finding him on the carpet with half his body off 🤦🏼‍♀️. He once fell off crawling off our V high super king when he was under 1 and scared the life out of me. Any suggestions mamas? X