I have filed my return this week but I just realized that I have made tax instalment payments to my Cra account that I did not claim on line 476. What should I do?

Since you have already filed your return- You will wait until you receive your notice of Assessment and make sure that they haven't already entered it for you. If not, then you will be able to file an adjustment.

https://turbotax.community.intuit.ca/replies/2647992