I'm sorry for your loss.
When you transfer your return from last year, right at the beginning TurboTax asks if anything has changed. This is where to let TurboTax know that your wife passed away. Then, TurboTax will let you know that your returns can't be prepared together this year and give the option to separate the returns.
Here's how to start a new return: https://turbotax.community.intuit.ca/replies/3288128
