Can MBED Studio be used with nRF52811

I came across this post in the MBED forum “Custom and community boards” category, which hinted at a method on how to implement creating a customer config.

But I still need help as the documentation on configuration system (https://os.mbed.com/docs/mbed-os/v6.2/program-setup/advanced-configuration.html) does not explicitly show you how to change flash/RAM size, for example.