Thank you all. I'm already enrolled in Nexus. I recently applied for the APEC and got conditionally approved.Next step is to visit an enrollment centre for a signature collection. I tried to setup an appt at the YYZ Enrollment Centre but the earliest availability they have is mid-June. Someone recommended that I instead do it at the enrollment on arrival centre. I've researched everywhere about the YYZ enrollment on arrival and so far I know that it's located on Terminal 1-Booth 18 or 20 but I'm confused because to my best knowledge there aren't any CBP offices in Arrivals.