To find a specific Action within the app, use the Search bar in the top of the app screen. You can search by Action name if you know it, or use any keywords related to the action you're looking for. If it is an Action you have recently logged, look no further than the Recent category from the Category View. (The Recent category icon resembles a clock.)
If you've come up with a new Action that you want to share with others, you can log in with Your Own Green Action -- find it with Search.