Basically, you need to be with a CM. Certain times of the year, they give CMs "Friends and Family" tickets where 2 people can go to Company D. Usually happens in November.
ETA - If you do get a CM ticket to go, there are items that are Cast Member only.
And more - The tickets are limited to 2 people. In our experience, they have allowed a young child, but teens are counted in the 2. We had 2 tickets, 3 adults and a 12 and 14yo. Only one teen was allowed in. (They took turns so mom could get them stuff.)