Initial Leveling of Simple Project

[Crit]

I'm thoroughly confused by what has to be a simple problem. I've started a project of several chains of tasks, where three or four are linearly dependant, and there are 5 or 6 groups of these. The first task in each group is to be performed by "Tom", but Project has Tom assigned to each of the 5 or 6 first tasks and tells me he's overallocated.

I want Tom to start group 2 once he's done with Group 1, and someone else will take over on Group 1.... and so on. Any idea why Project insists that Tom start every group on Day 1? I've set the calendar, his max units are 100%, but he's still overcommited. Any ideas?

 

[PDQBach]

If you don't tell us about the tasks, predecessor/successor linkages and resource assignments no one can possibly help.