If you use Android Studio to create an app using Android chart, you can download directly the jar containing all the classes and add it to your project. When the download is completed, you should add the library under libs folder so that I can be included automatically into your project. Now you are ready to use the lib!
When creating a charts in Android, you need usually a set of data that has to be drawn in the chart, in this case to have real values and to not re-invent the wheel we can suppose we get these values using WeatherLib so that we will plot the atmospheric parameters (like temperature, and pressure..).
There some basic concepts that stand behind this library and they are important so that you can use it: