Why can't I join a domain in Windows 10?

[beerabuser30]

I setup a Windows 2012 essentials server. I followed this http://www.groovypost.com/howto/join-a-windows-10-client-domain/ but Join a Domain isn't there. How do I get it to show it up? I have also tried to use the Windows 10 connector and it isn't finding my server