Thank you Steve for reaching out, I originally set this up using webhooks but found that the option I have with a timer function and cloud message queues are more performant. I still kept the WebHook code in there, since it may be useful for some scenarios.
The EnableSubscriptions.ps1 in the investigations folder is starting the subscriptions needed for the scheduled function. Please use the blog post steps to set the timer function up, I never created a dedicated .md for that config.
The one in the root works with the description I have in readme.md
If you stick to the description on the repo and use https://github.com/OfficeDev/O365-ActivityFeed-AzureFunction/blob/master/ActivityFunctionApp.ps1 you can use the webhook function. Which is enabled by EnableSubscriptions.ps1 in the root. “Steps to Create the Azure Function”
Sorry for the confusion,
Jon