1. Download the source (a ZIP file) from http://arrsoft.com/examples/CallFriends.zip.
2. Upload the zip file to My Projects using the More Actions / Upload Source buttons.
App Inventor's web software portion automatically opened the ZIP file and loaded it into the Design screen. You have all the graphics of my completed app and the design of all three screens.
Open the Blocks Editor and you'll find (a portion shown in the next screenshot) the complete blocks with lots of explanations. If you don't see the explanation balloons, just left-click on the small black boxes with white question marks. Click on them again to hide the balloon.
Referring back to the figure before last, the app's first screen, let's consider the design parameters for the CallFriends app. What do we need it to do? Well, three basics:
Select a friend's name and number, make the call
Add the names and numbers of new friends
Edit or Delete names
This is an easy way to start...