Run Macro after data is loaded

We have a third party software program with some simple custom reports(created by Acess queries from the main d-base). Users can select a custom report in the GUI to execute the report. Then, the third party program program launches Excel and displays in the queried info, but the data needs to be reformatted a bit (adding subtotals, formatting subtotal lines, adding units of measure to the newly created subtotal lines and etc.) through a macro but the macro has to wait till the data is pulled in before it begins. Is this possible? Thanks for any advice

Thanks for the reply. My skill level is not very high in these matters so I can't create a report. But I'll explain the process of the events so you'll have a better idea of my situation.
The third party software (Aspen) has a user d-base (which links with the main d-base upon opening) and in the user d-base I create custom queries in access, view them in SQL, then copy and paste them in a custom query data table within the user d-base. Also, in the user d-base, there is a custom report table where I specify the report template file name, file location, file type (Excel), worksheet name, & etc. The new report (or Excel worksheet template customized to accept the queried data) appears in the GUI for selection. Once selected and executed the Excel template opens and the data from the predefined query pouplates the worksheet. My problem is that I need to insert and subtotals into the sheet and format the subtotal rows and have this function executed automatically, but when I choose the VBA function "Private Sub Workbook_Open", to execute the macro automatically, the macro executes before the data from query is there? Is there any way to ask the Macro to wait till the data is in the worksheet before executing. Thanks for the help.

Ok. Probably will do that. Thanks for your time on this.