All you need to do is write a script that creates the records and puts the data you want into it. Have you used FileMaker's scripting engine. In many ways it is a combination of SQL and PL/SQL and basically does all of the automated actions in FileMaker.
FYI, FileMaker's ExecuteSQL only supports SELECT statements, but FileMaker is fully SQL compliant. So you can use an external program to INSERT or DELETE or whatever other SQL functions or you can get a FileMaker plugin that lets you use SQL calls. However, you'll end up back in FileMaker's scripting engine to use them because if you want someone to push a button, the only thing FileMaker can do to start a procedure is execute a Script.
The script would be something like:
[Start at Employee Table I assume or wherever you Button is]
Set Variable [$EmployeeID; Value: EmployeeFile::EmployeeID ]
--- You might get the start and end dates from a field or from a Show Dialog Box or however you get the dates
Set Variable [$StartDate; Value: <insert start date field>]
Set Variable [$EndDate]; Value: <insert end date field>]
Set Variable [$LoopDate; Value: $StartDate - 7]
Go To Layout [TimeSheetLayout ]
Set Variable $LoopDate; Value:$LoopDate + 7
Set Field [TimeSheet::EmployeeID; $EmployeeID]
Set Field [TimeSheet::StartDate; $LoopDate ]
Set Field [TimeSheet::EndDate; TimeSheet::StartDate + 6]
Exit Loop If [TimeSheet::EndDate > $EndDate ]
Go To Layout [Original layout]
That works. Thanks.