I have made contributions to my RRSP during the tax year. However, I do not want to claim all the RRSP deduction during the current tax year, I want to carry forward a portion of it to the next year.

Go to 'Form Manager' and search for the form 'RRSP Contributions'. In the section called 'RRSP Contributions' on the first page, enter the contribution you want to claim at 'Actual contribution claimed'. Please note that your unused contribution will be carried forward.