I need to explain to somebody step by step how to go through the process of signing a message to verify they own the private keys associated with an address containing funds. This is to ensure ownership before a sale is agreed.
What is the simplest and easiest way to do this (so that I can get them to understand my instructions and be able to follow through)?
I know this can be done a number of ways (bitcoin core, Electrum, Using a Ledger or Trezor, or a browser based tool .
I appreciate any input.