To enter this place you have to do two things.

1. Get into a coma
2. Get Chosen by Rosemary

To get chosen by Rosemary (the ruler of Dreamcord) isn't something easy. Although she has a high chance of choosing you, she often also chooses you depending on her mood. + points if you are a hopeless individual who didn't enjoy it in the real world so she knows that you would like it here more. She only can see what your backgrounding story is and not your present self.