When you set up the Sisra Excel Add-In for the first time, you will need to add your school's unique Add-In code, which enables the Add-In to link to your Staff Filter Profile/Class Context Profile in Observe.
You can find your Add-In code on both the Staff Import, and Class Import pages in Observe. Navigate to Admin > Data > Staff > Staff Import (or alternatively Admin > Data > Classes > Class Import), then your 9 digit code can be found above the Choose File button.