Setting up gpg for verification

Verification needs one tool and about ten minutes of setup, done once. Everything after that is a single command you can run without thinking about it.

What to install

GnuPG on a desktop, which most Linux systems already have and which is a standard package everywhere else. On Windows and macOS a graphical front end wraps the same engine and produces the same answers. There is no advantage to the graphical version beyond comfort, and there is a real disadvantage if it hides the output line that actually matters.

What a keyring is

A local file holding public keys you have collected. Importing a key puts it there. Nothing about importing implies you trust the key or believe anything about its owner, it only means your machine now has a copy to check signatures against. People hesitate at this step as though importing were an endorsement. It is not.

Importing the operator key, once

Obtain the public key block. Collect it from more than one place if you can.
Compare the fingerprints from those places against each other before importing anything.
Import the block into your keyring.
List the key locally and confirm the fingerprint matches what you compared.

That sequence happens one time. Every announcement afterwards is checked against the key already sitting in your keyring, which is the whole reason this is worth the initial effort.

Do not do this in a browser

Web pages offering to verify a signature for you are asking you to trust the page instead of the mathematics. The entire value of a signature is that checking it requires trusting nobody, and handing the check to a website discards exactly that. Run it locally or do not run it.

What you do not need

A key of your own. Verification uses the operator public key and nothing else. Generating a personal key is useful for encrypting messages to a vendor and is unnecessary for checking whether an address announcement is genuine.