I tried the free subscription. I liked the version CC. Recently bought a full subscription (to mail the letter with proof of payment), but the lists of subscriptions on my profile anyway worth "Free Trial" and the app CC offers to download demo versions of software, and when any of them offers start a trial period or a serial number, which I do not know. What's the problem, can anyone explain? Sorry bad English
Please click on "License This Software" when the trial window pops up.
Then enter your Adobe ID and Password to activate your product.
If it asks for a serial number refer to the below link.