Normally, you would get the UCC from your last year's CCA calculations. Did you buy a new asset this year, or is it something you owned previously but are only taking CCA on this year?
If you have TurboTax Live Assist & Review, here is how to talk to a Tax Expert: https://turbotax.community.intuit.ca/community/navigating-turbotax/help/i-m-using-turbotax-live-assist-review-how-do-i-talk-to-a-tax-expert/00/873764