In order to create new Forest and promote Windows Server 2012 Core to be Domain Controller for that Forest, first Active Directory Services Role has to be added:

Install-WindowsFeature AD-Domain-Services –IncludeManagementTools

Once Active Directory DOmain Services role is installed we can promote server to be first Domain Controller in the Forest.

Install-ADDSForest -DomainName "lab.corp" -DomainNetbiosName "LAB" -DomainMode Win2008R2 -ForestMode Win2008R2 -InstallDns -Force

And after some time new Forest and Domain Controller is ready to use.