Hi,
Actually, you may be very lucky today. We have a section that you can install via the Store that will allow you to enter the information you see without writing a hook. This is the Section page:
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Another option might be the premium Hooker Plugin, combined with the free Action Map will help you identify the proper hook, then the Hooker plugin lets you place code without having to edit the functions.php.
However, given the multisite aspect of this, I think the first option is safest.