Added building guide

Documentation/BUILDING.md

@@ -0,0 +1,63 @@
+# Building
+## Prerequisites
+The build system of this repository is based on Make. The `Makefile` is in the base of the repository.
+
+Firstly, figure out which MCU platform your supported board is based on. The table below can help you.
+
+| Board name | Link | Transceiver | MCU | Description | 
+| :--- | :---: | :---: | :---: | :---: |
+| Handheld v2.x RNodes | [Buy here](https://unsigned.io/shop/product/handheld-rnode) | SX1276 | ESP32 |
+| RAK4631 | [Buy here](https://store.rakwireless.com/products/rak4631-lpwan-node?m=5&h=wisblock-core) | SX1262 | nRF52 |
+| LilyGO LoRa32 v1.0 | [Buy here](https://www.lilygo.cc/products/lora32-v1-0) | SX1276/8 | ESP32 |
+| LilyGO T-BEAM v1.1 | [Buy here](https://www.lilygo.cc/products/t-beam-v1-1-esp32-lora-module) | SX1276/8 | ESP32 |
+| LilyGO LoRa32 v2.0 | No link | SX1276/8 | ESP32 | Discontinued? |
+| LilyGO LoRa32 v2.1 |  [Buy here](https://www.lilygo.cc/products/lora3) | SX1276/8 | ESP32 | With and without TCXO |
+| Heltec LoRa32 v2 | No link | SX1276/8 | ESP32 | Discontinued? |
+| Heltec LoRa32 v3 | [Buy here](https://heltec.org/project/wifi-lora-32-v3/) | SX1276/8 | ESP32 | 
+| Homebrew ESP32 boards | | Any supported | ESP32 | This can be any board with an Adafruit Feather (or generic) ESP32 chip |
+
+### ESP32
+If your board is ESP32-based, please run `make prep-esp32` to install the required BSP and libraries for that target.
+
+### nRF52
+If your board is nRF52-based, please run `make prep-nrf` to install the required BSP and libraries for that target.
+
+## Compiling
+Next, you need to find the name of the target for your board. Please reference the table below to do so:
+| Board name | Target | 
+| :--- | :---: |
+| Handheld v2.x RNodes | `rnode_ng_20` |
+| RAK4631 | `rak4631` |
+| LilyGO T-BEAM v1.1 | `tbeam` |
+| LilyGO T-BEAM v1.1 (SX1262) | `tbeam_sx126x` |
+| LilyGO LoRa32 v1.0 | `lora32_v10` |
+| LilyGO LoRa32 v2.0 | `lora32_v20` |
+| LilyGO LoRa32 v2.1 | `lora32_v21` |
+| Heltec LoRa32 v2 | `heltec32_v2` |
+| Heltec LoRa32 v3 | `heltec32_v3` | 
+| Homebrew ESP32 boards | `genericesp32` |
+
+After you've ascertained the target for the board simply run the following to compile for the board:
+
+`make firmware-[target]`
+
+Ensure you replace [target] with the target you selected. For example:
+
+`make firmware-rak4631`
+
+## Flashing
+To flash the chosen board (if you have one), simply connect it to your computer over USB, and then run the following:
+
+`make upload-[target]`
+
+Ensure you replace [target] with the target you selected. For example:
+
+`make upload-rak4631`
+
+**Please note**, you must re-compile the firmware each time you make changes **before** you flash it, else you will just be flashing the previous version of the firmware without the new changes!
+
+These commands can also be run as a one liner. For example:
+
+`make firmware-[target] && make upload-[target]`
+
+This is especially helpful when making continuous changes to the firmware and testing them out.

Documentation/FAQ.md

@@ -1,4 +1,6 @@
 # Frequently asked questions
+## How do I build this firmware?
+Please see [BUILDING.md](BUILDING.md).
 ## Can I produce and sell my own RNodes using this project? 
 Yes! Feel free to use the firmware in this repository for your produced RNodes. You do not have to pay a license to use this software commercially, as it is licensed under the GPLv3. If you fork it, you must understand your obligation to provide all future users of the system with the same rights that you have been provided by the GPLv3. Please also consider contributing additional features you design to this repository, to allow others to also use them.