Update TOC

doc/sphinx/how-to/index.md

@@ -6,6 +6,7 @@ These how-to guides cover the key aspects of working with Miaspects of working w
 - [Getting involved in Mir](getting_involved_in_mir): first steps to contributing to Mir
 - [Using checkbox-mir](how-to-use-checkbox-mir): validating your environment using [checkbox-mir](https://snapcraft.io/checkbox-mir)
 - [Calibrating a touchscreen device](how-to-calibrate-a-touchscreen-device): creating and using a calibration matrix using [the libinput snap](https://snapcraft.io/libinput)
+- [Enabling graphics-core-22 on a device](how-to-enable-graphics-core22-on-a-device): creating a `graphics-core22` provider snap for a new board
 
 ```{toctree}
 :hidden:
@@ -15,4 +16,5 @@ developing-wayland-extension-protocols-for-mir-servers
 getting_involved_in_mir
 how-to-use-checkbox-mir
 how-to-calibrate-a-touchscreen-device
+how-to-enable-graphics-core22-on-a-device
 ```