Locations are useful to organize the company without creating segmentation. Not all companies will require locations. Creating Locations are very similar to Departments
Standard import & export interfaces are already in the system by default. If you are not looking to import or export anything specific from Harmony T&A, you do not need to set up custom interfaces.
Your timesheet periods refer to the period of which your timesheets are for. Often, this is identical to your pay periods in payroll. You can review your timesheet periods by navigating to Setup > Timesheets.