P.P.
I went through a similar situation with my daughter. We put a chair in her room and would sit with her until she fell asleep. The first night she cried for about 45 min. I never picked her up, but I would talke to her to calm her down. She finally layed down by herself. We did that every night for about a week, the crying getting shorter and shorter. After a week she would just lay down and go to sleep. The big thing is just not picking them up. They will learn.
Hope this helps.