Please help me walk through this problem by using excel to make early and late start schedules to find slack and please show how you found the numbers! Then identify the critical path so we can find the impacts of the elements being variable. Please use excel tables so I can try this myself I just want a better understanding of this topic

Activity 1 Select vendor 2 Hire Finance module consultant 3 Hire Materials Mgmt consultant 4 Develop internal team 5 Select hardware system 6 Implement hardware system 7 Develop Finance interfaces 8 Install Finance module 9 Test Finance module 10 Put Finance module on-line 11 Develop Materials Mgmt interfaces 12 Install Materials Mgmt module 13 Test Materials Mgmt module 14 Put Materials Mgmt module on-line 15 Develop Finance user training 16 Develop Materials Mgmt user training Duration 1 week 4 weeks 4 weeks 10 weeks 3 weeks 8 weeks 8 weeks 3 weeks 2 weeks 0 15 weeks 6 weeks 3 weeks 0 5 weeks 7 weeks Predecessors None 1 1 None 2,3 5 6 6 7,8 9 6 10,11 12 13 4,7 4,11