I Have A Question About The Primary Domain

Good Day WPMU...
I have installed WPMU Multi-Domain Plugin for my WordPress Multi-site install on wdxservices.com. The Question i have is were can i build on the primary domain. The option to build on that site is gone. can some one please help me out with finding it... lol... or shop me how to add it back.. I would like to keep the option to build on the primary domains domain as well as the new ones that i have added.BUT!, i don't want the people that get site to have the option to use the domain... i only want the add on domains to be used...

I have granted support access to the site... thank you and looking forward to your input...