The 'Sites & Tasks' menu lets you set up your customer sites aka job-sites, this features is used for automatic check-in and check-out employees etc. 'Tasks' menu let you setup tasks and assign it to your employees or groups - the employees can select the customers and job and indicate service hours - this feature helps generate custom reports per customer for your costing analysis, billable hours calculations including overtime etc
How to Setup:
Here is a quick overview video: