Create a Group Managed Service Account

Using PowerShell.

Create a new gMSA account:

New-ADServiceAccount -Name "gMSAuser1" -DNSHostName "gMSAuser1.mybusiness.local" -Enabled $True

Assign it for use by computer 'MYCOMPUTER':

Set-ADServiceAccount -Identity gMSAuser1 -PrincipalsAllowedToRetrieveManagedPassword MYCOMPUTER$