My tip would be if he gets out of bed and starts playing - let him. He will get back into bed when he's tiered
If he comes to the door and starts creating (only when he's crying/upset), don't make a fuss, avoid eye contact and gently pop him back in bed. You may not have to do this but then again you may have to do it a million times
Finally - be patient. Its all new to him and can be quite scary for them too, but he'll soon settle and remember in the morning to make a HUGE fuss about him sleeping the whole night in his big bed
Good luck and keep us updated. xx