Paper mario thousand year door?

Question:i am working on the last chapter and i am having trouble. i am at the save point going into a big room i have beaten the bad guys but when i go into another room with a staircase what am i suppose to do to go on. i went up the stairs and it brought me to the big room. then i went across it took to the big room what do i have do from there.

Answers:
im supposing touve been through the thousand year door,
you go down the staircase, go through all the traps battle the queen, then theother queen where princess is traped in, and *ding* finish!