Follow these steps if you received a code for a free trial:
To view and or update your account details, click My Account in the top menu, then click My Account again. Here you will be able to view your purchases and subscriptions, update your personal info, and update payment details.
It looks like this:
Click on the My Account in the top menu. Go to the “Subscriptions” tab and click “Cancel”.
Go to these links for tutorials: