If you bought TurboTax Desktop, you need to download the software onto your computer from this link: 

https://turbotax.intuit.ca/tax/software/download

Install it, and, as you follow the steps, the application will ask you to activate your product. Here's a link explaining all the steps involved in installing the Desktop version

https://turbotax.community.intuit.ca/turbotax-support/en-ca/help-article/install-products/understand...

If you have bought TurboTax Online, please go to turbotax.ca/activate to use your code before you start your returns. You can see this TurboTax FAQ for step-by-step instructions: In TurboTax Online, how do I use a prepayment code? 

Please keep in mind that the code can only be used once per account. Using the code again will result in an error message. It can only be linked to one account. Additionally, TurboTax Online and TurboTax Desktop codes are not interchangeable. 

Thank you for choosing TurboTax.