I have been struggling to figure out how to calculate the early start and Early finish. I cant remember what numbers in the chart to use to find these. Would some be able to help me?

D15 X V fx A B C D E Activity code Actual Optimistic Pesimisitic Order 2 A 3 4 5 - 3 B 5 9 - 4 3 10 A u 2 5 8 B 6 1 7 7 B 3 5 7 CD 8 G 7 8 9 DE 9 H 2 6 10 F 10 11 1. Calculate Early Start and Early Finish 12 13 2. Find the Variance 14 15 16 17