Catch 8 of the silver shining rabbits that randomly appear and the 8th one will give you the key. There's an easy way to do this that I found on GameFAQs:
Yoshi must enter the castle grounds through the front door. There are three rabbits at the end of the bridge and three more elsewhere in this area. If none of them are glowing then go back in the castle and out again and repeat etc. etc.
To unlock a door with a key, insert the key into the keyhole and turn it in the direction that opens the lock. Make sure the key is fully inserted and turned all the way to unlock the door.
To unlock a door, you typically need a key or a code. Insert the key into the lock and turn it to the right to unlock the door. If it's a keypad lock, enter the correct code to unlock the door.
Unlock the car with the key in the door or with the remote.Unlock the car with the key in the door or with the remote.
With a key.
Unlock it from inside the car with the door lock.
you use the key just like using the key for a door
you use the key just like using the key for a door
To unlock the passenger door of a Peugeot 307, you can use the key fob to remotely unlock the vehicle or manually unlock it using the key in the door lock. If the remote is not functioning, insert the key into the passenger door lock and turn it to unlock. Additionally, if you have access to the driver's side, unlocking that door will also unlock all the other doors, including the passenger side.
Unlock the car with the remote or the key in the door.Unlock the car with the remote or the key in the door.
Unlock the car with the remote or with the key in the door.Unlock the car with the remote or with the key in the door.
To unlock a door, you typically use a key or a code to disengage the locking mechanism, allowing the door to be opened.
You have to get enough stars to unlock the star door(the one where peach is crying out for Mario) and when you beat Bowser you'll get a key for the basement type area. To get there you go through one of the doors underneath the stairs and go down the stairs there and unlock it.Then you get enough stars to unlock the next star door and then you beat Bowser again and then you will get a key for the door leading to the third floor,or second floor in your case.