Planner Admin PowerShell Pre-requisite Error

Hi, I'm new to PowerShell and hope somebody can help out. I'm trying to meet the prerequisites before running scripts to configure M365 Planner as per this Microsoft Link.

At step 2 when I run the command;

Import-module "C:\Windows\System32\WindowsPowerShell\v1.0\Modules\PlannerTenantAdmin\plannertenantadmin.psm1"

PowerShell displays the error;

Exception calling "LoadFrom" with "1" argument(s): "Could not load file or assembly
'file:///C:\Windows\System32\WindowsPowerShell\v1.0\Modules\PlannerTenantAdmin\Microsoft.Identity.Client.dll' or one
of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)"
At C:\Windows\System32\WindowsPowerShell\v1.0\Modules\PlannerTenantAdmin\plannertenantadmin.psm1:8 char:1
+ [Reflection.Assembly]::LoadFrom("$path\Microsoft.Identity.Client.dll" ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [], ParentContainsErrorRecordException
    + FullyQualifiedErrorId : FileLoadException

Import-module : The specified module
'C:\Windows\System32\WindowsPowerShell\v1.0\Modules\PlannerTenantAdmin\plannertenantadmin.psm1' was not loaded because
no valid module file was found in any module directory.
At line:1 char:1
+ Import-module "C:\Windows\System32\WindowsPowerShell\v1.0\Modules\Pla ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ResourceUnavailable: (C:\Windows\Syst...enantadmin.psm1:String) [Import-Module], FileNot
   FoundException
    + FullyQualifiedErrorId : Modules_ModuleNotFound,Microsoft.PowerShell.Commands.ImportModuleCommand

On the surface it looks like files can't be found however all files are in the correct place;

Can anybody please point me in the right direction on how to fix this?

Thanks in advance!

Simon