Collection of App Inventor 2 Tips

Here is a collection of App Inventor 2 tips which I find very helpful. More will be added when I come across them in the future.

General / Beginner

Android Development for Beginners
https://www.youtube.com/watch?v=ugWu3gyte4I

AI2 Text Blocks
http://appinventor.mit.edu/explore/ai2/support/blocks/text.html

AI2 http://appinventor.mit.edu/explore/content/math-blocks.htmlMath Blocks

Example 1. How do you start and pause a sound file when the user clicks a button?
http://www.appinventor.org/content/howDoYou/Conditionals/startStop