I can’t tell a “fun” way to put them in their bed because that doesn’t exist. They got used to sleep with you so they have to get used to sleep in their room. You can put them in their bed at sleeping time and wait their with them until they fall asleep. If you stroke their back or pet/pat their bottom, they go to sleep quite fast. If you are their with them in the first some months (until they get used to it) than they will be fine.
The other question why they wake up during the night: it can be because they are cold. Try to make sure they are enough warm. They can kick the blanket off so if you put a nice and warm pyjama or sleeping bag on them it helps.
– If they wake up in the middle of the night, don’t let them go into your bed and sleep there. Go into their room and if nothing helps, lay down next to them in their bed until they go back to sleep and after sneak back into your room.
– I know it is not nice to hear that they are crying but if you let them sleep with you they will have never got used to their room. It will take up some months until they will settle down in their room. Put loads of cuddly toys in their bed so they won’t feel alone, make sure they are not hungry when they go to the bed because they can wake up in the middle of the night because of their empty tummy. Put a baby monitor in their room, so you can hear when they are crying so you can go into their room and not the other way around.
– Make a ritual around bedtime. Dinner, bath, go to the bed, sit their, talk to them, read a story, turn off the light and let them sleep. Usually 10 – 15 minutes what you have to stay with them until they fall asleep.
– If they are not calm, you can use lavender essence/scent in their room or with their bath to make them calm and ready for the bed. Don’t let them run around before bedtime because that makes them hyperactive and it will be much harder to put them into the bed and asleep. Do something nice and calm, like drawing, reading a story, look at a book with pictures and let them talk about it. The main thing that they have to feel they are safe in their room. And even you don’t sleep with them but you will go into their room when they need you. So they do not have to be afraid that they are alone or get lost, or mummy and daddy disappeared. Especially in the dark.