Hi Kabutoo, I'm a new user on a mac as well, too.
I stretched measures and used cut and paste of multiple measures.
I desire to move measures around, but I haven't found success.
Here's a link to the PDF versions of the manual: http://help.nchsoftware.com/help/en/crescendo/macappstore/help.pdf
I'll be searching that for ideas.
One tip in it is: Tip: While manually dragging notes around, you can hold down the Shift key to avoid accidentally changing the pitch of the note.
--Griff