The following are 5 sites to utilize for using the SharePoint Online Management Shell:
Get started with the SharePoint Online Management Shell:
https://docs.microsoft.com/en-us/powershell/sharepoint/sharepoint-online/connect-sharepoint-online
CMDLET References for the SharePointOnlinePowerShell:
https://docs.microsoft.com/en-us/powershell/module/sharepoint-online/?view=sharepoint-ps
Manage SharePoint with PowerShell:
SharePoint PowerShell:
https://docs.microsoft.com/en-us/powershell/sharepoint/
Intro to SharePoint Online Management Shell: