A resource is over-allocated when it's assigned more work than it can do in the time available, for example one crew on two full-day tasks on the same day. Resource leveling finds these conflicts and moves work so each resource has a workable load.
All the leveling tools are in the Actions menu:
Check resource levels
Go to Actions > Check Resource Levels.
gantterAi™ marks the tasks where a resource is over-allocated.
To remove the markers, go to Actions > Clear Resource level indicator.
Level resources automatically
Go to Actions > Auto-level resources.
gantterAi™ delays tasks where needed so no resource is booked beyond its calendar.
Review the new dates in the Gantt view. Leveling can push out your finish date.
Undo leveling
To return tasks to their dates before leveling, go to Actions > Clear & revert Leveling.
Tips
Set each resource's Base Calendar in the Resources view first, so leveling uses the right working days.
Save a baseline before you level, so you can compare the dates afterwards. See Creating and Using Baselines.