How and when can you get Luigi in this game?

I don't know when you can get Luigi but I got him really late in the game. I got Luigi when I had 70 stars. To get Luigi you need to be playing with Mario.

Now when you first enter the castle go to the left or the right doesnt matter and you should see a wooden door go through it and you should see big boo. Follow him into another door and you will see a bunch of ghosts when you get outside. Find the biggest ghost also known as big boo but not as big and push jump and R right over him. He should let out this thing that looks like a garbage can or something like that go near it and you will be teleported.

I think you need to beat 5 missions on that place then you can get luigi. heres how to get him. When you first walk in the big castle you will see that there is only 1 floor well guess what theres two. you just might not be able to see the second floor. When you first walk in the door go straight and do the triple jump. If at first you dont get it keep on trying. You'r eventually get there it's not impossible. After you get up on the second floor take a right then go to the end til you cant go no more. You should be in a place where there is book shelves and books that come after you.

You should see a question mark square outlined or not I recommend that you have the ? mark square but if you dont just go up there and do a backflip and you will be on a third floor. When you get on the third floor you should see a Luigi painting. Now again I don't know how many stars you need or if you need a question mark square. I recommend you do though. Just jump in the painting and beat the level and you have Luigi. If you do not have enough of something when you jump in the picture you will go down to the marry go round.

You get him after you get about 12 stars open one of the doors beside the stairs a gost is there follow it out the back door and go kill the big gost on the right of you. A evil looking thing will appear, go to it. Go to the libary and get the red box fly up and go through the door.

YOU GET HIM WHEN YOU GET 18 STARS!!
And wario when you have 31 stars.
And waluigi when you have all the stars.
And meta knight when you have all the stars.