To answer your previous question, you will see that our script extends Script. This is an abstract class in the OSBot API and since we are extending it, we have access to all of its attributes. An example of an attribute is inventory, whereby we are calling the super inventory object attribute and using the methods that it provides. As for the stall, you will find that that is initialised just above the snippet you quoted, we're creating an instance of an RS2Object which is an API object describing an ingame object.
Hope that makes sense, let me know if you're still unsure. Since you edited the post I would assume you figured this out yourself but I just thought i'd drop a quick reply in to clear it up if you didn't!
-Apa