Actually your STO account is also a global Cryptic account, but you still have to officially sign up on the Champions website to start playing the game if you've bought it or you are planning on signing up for the F2P when it goes live.
You should be able to use your STO account handle/password to sign in to the Champions account when you get a prompt to log in on the website. Unless they've changed things from more than a year ago, which I doubt.
I honestly can't recall the exact process I went through when I first signed up to the STO website as my Champions handle. It's been over a year since I did so. I just know it can be done and it wasn't difficult.
Thanks for your reply Xiaza But what if you have just bought the game and have a free 30 day pass and have yet to pick a Sub choice because you know the game will be free in a few days do i pick the 1 month 8.99 and then cancel after 30days is up and be then able to become a free player .. .. or should i just ignore the 30 days and wait for the f2p option ..
If one signs up for a new Champions account you will automatically be classified as F2P unless you sign up for a subscription or lifetime account.
If you already have a sub to the game you'll be able to keep it or convert to a F2P account simply by canceling your sub plan. You will be converted to a 'Silver' (F2P) account as soon as any remaining time is used up on your former sub plan.
If you used game-cards you will become 'Silver' when that time is up unless you sub or apply a new game-time card. I don't know if they will continue to offer those cards after F2P though.