Switching from co sleeping to toddler bed

So I have another question. My toddler is difficult. I never planned to co sleep, it just happened like that. From day 1 my son didn't sleep good in his bassinet and I was dead tired so I let him sleep with me. We both slept way better. Now he's 22 months. I want him in his toddler bed. I put it beside my bed. Because he still wakes up in middle of night for milk. I need help with that too. I'm expecting my third child next May and want him in his own bed. I'll be sure to keep my next baby in their own bed next time!