Mark,
not a direct answer to your questions, but Xojo is Object Oriented Programming all the way, event an integer variable is an object. VB6 was not OOP.
I suggest you get familiar with OOP, find an introduction on the Web. You will the learn what are classes, methods properties an events. Then get back to working with Xojo. Note that not all languages implements all of OOP, for example Xojo does not implement multiple inheritance. You will find Xojo a very good system.