I have created Postman collection for the Office 365 Usage Reports. Enjoy!

https://github.com/pankajsurti/O365UsageReportsAPIs

Office 365 Usage Reports – https://docs.microsoft.com/en-us/graph/api/resources/report?view=graph-rest-1.0

Office 365 Usage Analytics Adaption Package is located below.

https://docs.microsoft.com/en-us/office365/admin/usage-analytics/usage-analytics?view=o365-worldwide

Microsoft 365 usage analytics data model

https://docs.microsoft.com/en-us/office365/admin/usage-analytics/usage-analytics-data-model?view=o365-worldwide