Use the adress to log on with the password you set in registration.
Choose your preferred product(available for Mac and Windows) and download it.
Install the software by executing the downloaded file.
activaton of the product is done by using the activation key you received by mail (Activation codes for Windows and Mac differ, you'll get both with the License mail!)
if you loose the activation codes you can also obtain them from the website of CambridgeSoft. Please log in with your mail adress and your password, choose "My Account" and "My Downloads" there you will find the required information.