Fn-NewRosterPlanner.ps1

function Fn-NewRosterPlanner {
    param (
        [Parameter(Mandatory = $true)]
        [string]$Domain,

        [Parameter(Mandatory = $true)]
        [string]$UPN,

        [Parameter(Mandatory = $true)]
        [string]$NameOfPlanner
    )

    try {
        # Check if PnP module is installed
        $pnpModule = Get-Module -Name "PnP.PowerShell" -ListAvailable
        if (-not $pnpModule) {
            # Install and Import the PnP module
            Install-Module -Name PnP.PowerShell -RequiredVersion 1.12.0 -Force -scope CurrentUser
            Import-Module -Name PnP.PowerShell -RequiredVersion 1.12.0 -Force
        }

        # Connect to the tenant 
        Connect-PnPOnline -Url "$Domain.sharepoint.com" -Interactive 

        # Get the graph access token
        $Token = Get-PnPGraphAccessToken

        # Create a ROSTER PLAN
        $headerParams = @{
            'Authorization' = "Bearer $Token"
        }

        $requestBody1 = @{ 
            "@odata.type" = "#microsoft.graph.plannerRoster"
        }
        
        $RosterDetails = Invoke-RestMethod -Method Post -Uri "https://graph.microsoft.com/beta/planner/rosters" -Body $requestBody1 -Headers $headerParams
        $ID = $RosterDetails.id

        # Add one user to the roster
        $headerParams = @{
            'Authorization' = "Bearer $Token"
            'Content-Type'  = 'application/json' 
        }

        $requestBody2 = @{
            "@odata.type" = "#microsoft.graph.plannerRosterMember"
            "userId"      = $UPN
        }

        $AddMembers=  Invoke-RestMethod -Method Post -Uri "https://graph.microsoft.com/beta/planner/rosters/$ID/members" -Headers $headerParams -Body ($requestBody2 | ConvertTo-Json)

        # Creating the Planner Plan linked with the roster
        $headerParams = @{
            'Authorization' = "Bearer $Token"
            'Content-Type'  = 'application/json' 
        }

        $requestBody3 = @{
            "container" = @{
                "url" = "https://graph.microsoft.com/beta/planner/rosters/$ID"
            }
            "title"     = "$NameOfPlanner"
        }

        $Response = Invoke-RestMethod -Method Post -Uri "https://graph.microsoft.com/beta/planner/plans" -Headers $headerParams -Body ($requestBody3 | ConvertTo-Json)

        $URL = "https://tasks.office.com/$Domain.onmicrosoft.com/en-US/Home/Planner/#/plantaskboard?groupId=$ID&planId=$($Response.id)"
        $URL
        Start-Process $URL

    }
    catch {
        Write-Host "An error occurred: $_" -ForegroundColor Red
    }
}

# Call the function with parameters
Fn-NewRosterPlanner -Domain "Nectaa" -UPN "aman@nectaa.onmicrosoft.com" -NameOfPlanner "Bhola"