You should be able to set up your account using the email associated with your account. You will then have access to the download links for purchased products. Addendum: I'm assuming you are using the product purchased directly from Borisfx.
You should have received a download link in the email with your code, barring that, go here https://borisfx.com/products/continuum/ download the trial, install it and register using your code. It'll ask for that info at the end of installation.