The first time you launch Full you're guided through gestures used in the app. As you can see here, a swipe in either direction triggers different actions.
Adding a goal requires only two pieces of information: a title and the number of times you want to complete the task in a given month.
When you hit your target, you're rewarded with a pop-up like this one. Good work!
You can visualize your progress when looking at the list, or by activating the view seen here. You can't add or subtract from your goals in this view, but it looks nice.