Your taxes for tax year 2018 are what you'll be preparing and filing before April 2019.
You can download TurboTax for tax year 2018 (our most current version) from here: https://turbotax.community.intuit.ca/replies/3001486
@OmearaLinda This FAQ tells you how you can install TurboTax if you don’t have a CD drive in your computer: https://turbotax.community.intuit.ca/community/product-information/help/how-do-i-install-turbotax-on...
To download your CD/Download that you purchased from Costco see the link below for the various TurboTax version. Select the version that you purchased from the link below:
Then follow instructions to enter your installation key for your Cd/Download, please click on the link below for screenshots and detailed instructions: