|have you tried identifying the views for this app?? this might help you in achieving what you are going after for the app and create/answer questions to help you further along.
from what I am seeing so far I can envision at least 3 different views. one with the screen containing these two buttons you want and then a view that gets displayed for each button.
since in processing is a collection of orders you will probably have an array of some sort.
does all this information get sent to a server somewhere??
does the server store state of orders??
how do you talk to the server??
you really need to sit down and start asking yourself and your team (if you have one) a lot of questions about the app and what the problem is that you are trying to solve.
you want something inspirational??