Advice on transitioning my 18 month old to his toddler bed

Francesca
Hello,
I'm writing to get any ideas or experiences you parents may have had with this kind of situation. I have an 18 month old and am 34 weeks pregs. I want to transition my first to a toddler bed so he can get used to it by the time second baby arrives. My first is used to sleeping in his own room since 5 months old and has no problems falling asleep. Again any advice or suggestions for how to help my son transition would be greatly appreciated.