An add-in sheet is a worksheet where totals from other worksheets are summarized and displayed. These sheets can be used to provide an overview or summary of the information in your workbook, which may make it easier for you to find what you’re looking for. Add-in sheets are column-oriented; they begin with a heading row and contain one column for each data item that will be summed up on the sheet.
You can create an add-in sheet by following these steps. This is what it would look like after you complete this step. In many cases, the values in your worksheet might change from week to week or even from day to day. If so, then you’ll need to update your summary tables accordingly when new information becomes available.
You may find it helps keep track of which cells have been updated using conditional formatting rules (the icon looks like two sets of double lines). To do this, go back into Design mode and select “Conditional Formatting”.