co-op program length

[rutuldesai]

I got an offer letter for advanced diploma in supply chain management with work experience(B162) for January 2020. In which co-op work is mandatory to get the diploma.
In the offer letter, this has been written
"Program of Study: Business Administration - Supply Chain and Operations Management (B162) Certification: Ontario College Advanced Diploma
Length of Program: 3 years (6 semesters in class, 2 semesters work experience)
Start Date: January 6, 2020
Work Semesters: After Semester 3 (Minimum 10 weeks or 360 hours per work term)*
Work Duration: Any time between January 11, 2021 and August 19, 2022
Type of WIL: Work Experience**
&
"Program Level Ontario College Advanced Diploma
Start Date January 06, 2020
End Date August 19, 2022 "
My question is, do I have to finish my co-op work after 3 years of study (3+1) or I have to finish it during my study? So, how long it will take me to get a diploma. 3 years or 4 years? Please give an update ASAP. Here is a program link
https://www.georgebrown.ca/programs/business-administration-supply-chain-and-operations-management-program-with-work-experience-b162/