Trying to learn-brand new- user does not have the same theme as I do

I am trying to figure this all out. I am trying to set up WPMU for my real estate company so that each agent can have their own blog. I paid wpmu dev to install it for me- that was great. I have a bare bones nelo theme that shows on the site and wanted the same theme for the new users. When I did a test one, it was not nelo. What am I doing wrong?