adobe muse serial number

I BUY AODBE MUSE, A MONTHLY PLAN. I INSTALL CREATIVE CLOUD, DOWNLOAD MUSE. BUT WHEN I TRY TO OPEN IT, IT ASKS FOR A SERIAL NUMBER.

WHERE DO I GET IT FROM? IT SAYS THAT MY TRYOUT PERIOD IS OVER, BUT I JUST BOUGHT A MONTHLY PLAN.

PLEASE HELP ME, I'M A GRAPHIC DESIGNER, FROM CHILE

THANKS