Add installation instructions.

README.md

@@ -9,6 +9,15 @@ A simple Flipper Zero application for NMEA 0183 serial GPS modules, such as the
 
 Heavy lifting (NMEA parsing) provided by [minmea].
 
+## Installation
+
+1. Navigate to the [FAP Build](https://github.com/ezod/flipperzero-gps/actions/workflows/build.yml)
+   GitHub action workflow, and select the most recent run.
+2. The FAP is built for both the `dev` and `release` channels of the official
+   firmware. Download the artifact corresponding to your firmware version.
+3. Extract `gps_nmea.fap` from the ZIP file to `apps/GPIO` on your Flipper
+   Zero SD card.
+
 ## Usage
 
 This is a single-screen app, and a few interactions are provided via the
@@ -44,6 +53,5 @@ please submit a PR adding it to the list.
 
 [Adafruit Ultimate GPS Breakout]: https://www.adafruit.com/product/746
 [minmea]: https://github.com/kosma/minmea
-[flipperzero-firmware]: https://github.com/flipperdevices/flipperzero-firmware
 [qFlipper]: https://flipperzero.one/update
 [u-blox NEO-6M]: https://www.u-blox.com/en/product/neo-6-series