##Tenant and App Specific Values
##Add the ones that you captured during the Azure portal piece here!
$appID = "<< replace with your application ID >>"
$appSecret="<< replace with your application secret>>"

$tokenAuthURI = "<< Replace with your OAUTH 2.0 TOKEN ENDPOINT >>"

##We create a small text body with the values
$requestBody = "grant_type=client_credentials" + 
    "&client_id=$appID" +
    "&client_secret=$appSecret" +
    "&resource=https://graph.microsoft.com/"

##Then we use the Token Endpoint URI and pass it the values in the body of the request
$tokenResponse = Invoke-RestMethod -Method Post -Uri $tokenAuthURI -body $requestBody -ContentType "application/x-www-form-urlencoded"

##This response provides our Bearer Token
$accessToken = $tokenResponse.access_token

##We set up which Graph endpoint we want to call (See https://graph.microsoft.io for more!)
$groupsListURI = "https://graph.microsoft.com/v1.0/groups"

##Then we make an authenticated request to the Graph API specified using the Bearer Token in the authorisation header.
$graphResponse = Invoke-RestMethod -Method Get -Uri $groupsListURI -Headers @{"Authorization"="Bearer $accessToken"}

#And then just walked through the nicely formatted PowerShell object it returns.
foreach ($group in $graphResponse.value)
{
    write-host $group.displayname
}