Few questions about coincidence generator and other stuff

[AK98]

Hey guys, i can't find something that helps me. Maybe you guys can. 

(Sorry, if my english isn't the best)

1. So i want 3 buttons on the home. Each button should be able to start one of the 3 different lists. 

The lists should be like: Some text appears and if i click on the screen, another random text of the list shall appear. The text should not appear a second time, not until i start the app again. 

2. Can someone explain to me, or show me a video where i can see how to set a button enabled, after you pay for that one?

3. How can you update an app, after it is uploaded in the app store? 

Thank you very very much guys! 

With kind regards 

Alex