Unfortunately, you can't claim mortgage payments for a new home, but you may qualify for the Home Buyers' amount, which is a tax credit available for first time home buyers:

https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-re...

The question regarding selling your principal residence is always asked on that page, you can ignore it if it doesn't apply to you.