Linkage w/ dynamically created objects?

I’m working on a tshirt design site. With all of the books I’ve read, it seems any class that I created has to have a linkage defined with an object on the stage. Otherwise the object instantiation throws errors on compile time. Is this not the case?

I’m having trouble seeing how I can allow the user create any number of custom text objects/or drop custom art objects with the only one object on the stage with the linkage to the class “custom text” or “custom tshirt”. Thanks.