"Discussion" button won't work from my browser.
And I can't find the button altogether on the iPhone app.
I really used to rely on it when learning new grammar rules :(
The iPhone app doesn't have a discussion section, alas. If you want to read more instruction, you may want to look for external resources.
When you do see it, are you viewing it from a desktop/laptop, or your phone's browser? What do you mean by "won't work"? Is the button grayed out, or does clicking on it just not do anything?