Hi Kim
It's a verson of controlled crying to teach your little one to settle themselves on their own/improve their sleep periods.
You put your little on in their bed, awake, at sleeptime
If they cry you go into them, pick them up and give a pat on the back and some shhing then put them back down in the cot and leave the room.
If they cry again you go back into the room and repeat the "pick up, put down" that you have just done.
You keep doing this until they go to sleep.
Is Rubie a good sleeper?
Lucy