Build and run the application on the iPhone 7 simulator, as you did earlier.
If building turns up any errors, you can view them in the issue navigator by selecting the 
tab in the navigator area
(Figure 1.26).
Click on any error or warning in the issue navigator to be taken to the file and the line of code where the issue occurred. Find and fix any problems (i.e., code typos!) by comparing your code with the code in this chapter. Then try running the application again. Repeat this process until your application compiles.
After your application has compiled, it will launch in the iOS simulator. Play around with the Quiz application. You should be able to tap the Next Question button and see a new question in the top label; tapping Show Answer should show the right answer. If your application is not working as expected, double-check your connections in Main.storyboard.
You have built a working iOS app! Take a moment to bask in the glory.
OK, enough basking. Your app works, but it needs some spit and polish.