I use the standard settings for the Matter examples.
So create a project from the example (eg Matter Light), then create a Build Configuration.
Select SDK (3.1.0)
Toolchain (3.1.0)
Target (nrf52840)
Base confg (prj.conf)
Extra Kconfig (mcuboot)
Optimize (debug)
Generate and Build
Debug with Ozone (flashes as well over Segger SWD).
From the serial monitor, grab the QRCode URL.
Using Apple Homekit (or Google Nest, or Home Assistant), add the device to your Matter fabric.
Select Add Anyway for “uncertified” device.