doc: update readme

README.md

@@ -2,9 +2,18 @@
 
 This is my personal ZMK config for the [temper](https://github.com/raeedcho/temper).
 
-Some notes about this config:
-- Four main layers (default, numbers/symbols, navigation, and function)
-- Default layer is Colemak DHm, but there's also a QWERTY layer that can be toggled on
-- Navigation layer has vim-like arrow keys
+## Installing
 
-![Temper Keymap](keymap_img/temper.svg)
+1. Flash all three microcontrollers with the reset firmware which has been build. All three with the same `.uf2` firmware.
+2. Flash all microcontrollers with their respective firmware
+3. Turn off bluetooth, plug in the dongle and everything should be working out of the box.
+
+## Building locally
+
+Change the paths in the environment variables in the `.build.sh`, then run it.
+
+```shell
+./build.sh
+```
+
+This will create a directory called `output` and in there are all the `.uf2` files