i believe it's like this
Round of 16
1. 1st place group A vs 2nd place group B
2. 2nd place group A vs 1st place group B
3. 1st place group C vs 2nd place group D
4. 2nd place group C vs 1st place group D
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5. 1st place group E vs 2nd place group F
6. 2nd place group E vs 1st place group F
7. 1st place group G vs 2nd place group H
8. 2nd place group G vs 1st place group H
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Last 8
9. Winner of match 1 vs winner of match 3
10. Winner of match 2 vs winner of match 4
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11. Winner of match 5 vs winner of match 7
12. Winner of match 6 vs winner of match 8
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Semi-finals
13. Winner of match 9 vs winner of match 11
14. Winner of match 10 vs winner of match 12
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Finals
15. Winner of match 13 vs winner of match 14