Enabling Dkim office 365

[siphongwenya]

Hi,

Im trying to enable Dkim on office365 as per

Enable DKIM for a custom domain in Office 365 in five simple steps - Altitude365

Enable DKIM for a custom domain in Office 365 in five simple steps

www.altitude365.com

I login to power shell but get the following error when I run
Get-DkimSigningConfig



Get-DkimSigningConfig : The term 'Get-DkimSigningConfig' is not recognized as the name of a cmdlet, function, script
file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct
and try again.
At line:1 char:1
+ Get-DkimSigningConfig -Identity mydomain.com | fl *cname*
+ ~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : ObjectNotFound: (Get-DkimSigningConfig:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException

Any advise will be appreciated. the domain is not hosted with microsoft