The amount of tuition paid is indicated on your T2202 tax form issued by your post-secondary institution.

So to clarify, turbotax has asked me to enter an amount for "Eligible tuition fees paid (all tuition fees paid for the eligible program certified on the Graduate Retention Program Eligibility Certificate)". You are saying I should only input the amount on my T2202 (which only shows one semester's worth of tuition), not all the tuition I paid for my program?

Also, is there somewhere I should be submitting my GRP certificate within turbotax since this is my first time claiming it?

It would be the total of all your T2202s.