README: add installation instructions

Author: chronopoulos

README.md

@@ -1,2 +1,10 @@
 # automato-arduino
-Arduino code for ESP32-based Automato Sensor Module.
+Arduino boards package for Automato
+
+## Installation Instructions
+1. Install [arduino-esp32](https://docs.espressif.com/projects/arduino-esp32/en/latest/installing.html)
+2. Add the [package index file](https://raw.githubusercontent.com/InterstitialTech/automato-arduino/main/package_automato_index.json)
+to the Arduino IDE (File > Preferences > Additional Boards Manager URLs)
+3. Open the boards manager (Tools > Board > Boards Manager), type "automato", and click Install
+4. Confirm that it's working by compiling Blinky with the board set as "Automato Sensor Module"
+