Updated README

README.md

@@ -1,4 +1,5 @@
-![bthome app](screenshots/bthome_app.png)
+![BT Home Controller in Bluetooth menu](screenshots/75c3eb86-5541-4c01-93ed-b0988b43bef0.png)
+![BT Home Controller app UI](screenshots/f311fb4e-8450-4b78-95a0-c938be21250f.png)
 
 This application turns the Flipper Zero into a [BTHome](https://bthome.io)
 beacon, and can be used to integrate the Flipper with home automation systems
@@ -9,19 +10,54 @@ over Bluetooth Low Energy (BLE). It allows devices to transmit sensor readings
 (temperature, humidity, battery level, button events, etc.) without requiring
 pairing or an active connection.
 
-The BTHome beacon is triggered when pressing the Flipper Zero "OK" button
-and currently includes the Flipper's battery percentage as a sensor.
+Pressing any direction on the Flipper Zero D-pad (Up, Down, Left, Right, OK)
+sends a BTHome button event. Each direction maps to a separate BTHome button
+object, so Home Assistant sees them as `button`, `button_2`, `button_3`,
+`button_4`, and `button_5` (OK, Up, Down, Left, Right respectively). Short and
+long presses are both supported. The Flipper's battery percentage is also
+included in each beacon.
 
-Unfortunately, due to the limited size of BLE packets the Flipper Zero can send
-there isn't much room left to add more sensors without removing the existing
-one.
+### Building
+
+Install [ufbt](https://github.com/flipperdevices/ufbt) into a virtual
+environment:
+
+```bash
+python3 -m venv .venv
+.venv/bin/pip install ufbt
+```
+
+Then build from the project root:
+
+```bash
+.venv/bin/ufbt
+```
+
+The first run downloads the Flipper SDK and compiler toolchain automatically.
+The finished app is written to:
+
+```
+dist/bt_home_controller.fap
+```
+
+### Installing on the Flipper
+
+Open [qFlipper](https://flipperzero.one/update), connect your Flipper via USB,
+and use the file manager to copy `dist/bt_home_controller.fap` to:
+
+```
+SD:/apps/Bluetooth/
+```
+
+The app will then appear in **Apps → Bluetooth → BT Home Controller** on the
+Flipper.
 
 ### Home Assistant setup
 
 The first step is setting up the [BTHome](https://www.home-assistant.io/integrations/bthome/) integration in Home Assistant.
 
-Once setup, the Flipper should be automatically discovered after pressing the
-center button once:
+Once setup, the Flipper should be automatically discovered after pressing any
+D-pad button once:
 
 ![home assistant discovered](screenshots/home_assistant_discovered.png)