Changing tempo on an imported audio file

Hello

I am not sure how to change the tempo on an imported audio file, not made in Cubase. It was imported as a
wma. file, now wav. I know it says something about it in the manual, but I dont understand it. I know you must look in the sample editor to do it. Anybody know how to?

Open the pool and make sure the correct original tempo of the clip is entered and that straighten up or musical is checked, depending on version. Put the track in Musical Mode.

Thanks, I will try that!