(README): Add initial installation docs

README.md

@@ -1,5 +1,35 @@
 # Genoswitch MP Firmware
 
+## Installation
+
+### Fetch submodules
+
+```shell
+git submodule init
+git submodule update --depth 1
+```
+
+### Toolchain
+
+To build this project, a number of extra tools and libraries are required.
+
+Here are the installation instructions for Linux.
+
+#### Debian-based distros
+
+```shell
+sudo apt update
+sudo apt install cmake gcc-arm-none-eabi libnewlib-arm-none-eabi build-essential libstdc++-arm-none-eabi-newlib python3 git nodejs
+```
+
+#### Arch-based distros
+
+~2GB install.
+
+```shell
+sudo pacman -S cmake arm-none-eabi-gcc arm-none-eabi-newlib arm-none-eabi-gdb arm-none-eabi-binutils python git nodejs npm
+```
+
 ## Licensing
 
 The codebase is licensed under MIT.