VBA Formula to show task list relevant to event dates across worksheets

Hi, I am new to the forum so please be gentle if I inadvertently breach etiquette!
I have a workbook with event details listed across several location worksheets. I want to extract from this a list of tasks that require actioning a certain time out from each event date. That is a list of what needs doing today, tomorrow...on Friday for instance. Task one might need actioning 5 workdays prior to the event date, task 2 on the event date and task 3, 10 workdays after the event date. I think I need to use VLOOKUP referring the event date to today/tomorrow/Friday so that it generates a list of all the registrations for each event that need tasks actioned on that day (That is, a chart listing Task, Event date, Location, Rego). I'm not too sure of the details of the formulas I will need though. Any suggestions?