Did you receive a back-payment of the Universal Child Care Benefit (UCCB) in tax year 2017? If so, you should have received an RC62 slip and you'll report this amount when you enter your dependant in your return.
If you're actually asking about the CCB benefit, the CCB benefit is non-taxable. You don't need to report it on your return.
https://turbotax.community.intuit.ca/replies/3234038
