First, at the beginning of the software in the tax profile, you need to specify that you receive UCCB benefits.  Then the software will prompt you, in due time, the screen for you to enter the amount you have on the tax slip.

Please keep in mind, that if you are a single parent, the income is considered income to the child, for tax purpose, and will be transferred.  This will reduce your income tax payable.

Hope this helps