Simply download the latest build for Mac, Linux or Windows and launch it. The desktop part of Flipper doesn't need any particular setup. See the relevant section in the sidebar for how to do that.
To see app specific data, you need to integrate the Flipper SDK into your app. Once you start Flipper and launch an emulator/simulator or connect a device, you'll start to see the device logs (and any other device-level plugins that work with your device). The native mobile SDKs for Android and iOS.Flipper helps you debug Android and iOS apps running in an emulator/simulator or connected physical development devices.