iPad App Icon size creation

Hello,

I am creating an App Icon and I am not sure of the size my files need to be.

I attached a screenshot of the files I need. I tried following that guide https://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/ MobileHIG/IconMatrix.html#//apple_ref/doc/uid/TP40006556-CH27-SW1

but it doesn't seem to work.

Thanks!

Isabelle