Event Dates: Great to include on the Project Info, as this will appear at the top of the Quote/Invoice for the client. Event Dates will not impact pricing or availability of your items.
Adjust your event dates under "Project Info"
Line Item Group Dates: If the Event Dates are added, the dates on the Line Item Groups will match the Event Dates. Line Item Group Dates will give a first pass at determining conflicts (until Logistics are added), and more importantly will determine the price for the Daily Priced items.
Line Item Group Dates
Logistics Dates: Logistics (or delivery dates) will take priority on determining conflicts and will determine the Tax required for that specific order.
Determine conflicts and taxes with Logistics