Open the downloaded file from your Downloads folder and follow the on-screen prompts.
While it could also refer to a for Android or the classic Fable: The Lost Chapters (often played on Android via emulators), I am focusing on the visual novel version as it is the only one typically released in "v0.4a" incremental updates. The Lost Chapters [v0.4a] [APK]
To play the latest build on your Android device, follow these standard steps: Open the downloaded file from your Downloads folder