The gpg output is dense and half of it is technical noise. This reading picks out the lines a reader actually cares about.
The line that matters
gpg: Good signature from "..."
This is the whole verification result. Everything else is metadata around it.
The line that means trouble
gpg: BAD signature from "..."
The message was altered after signing, or the signature was made with a different key. Do not trust the address inside. Report the bad post so other readers see the warning.
The line that means you need to import
gpg: Can't check signature: No public key
The operator key is not on your keyring. Import it (see the previous reading), then re-run gpg --verify.
The line that means the message is from someone else
gpg: Signature made ... using RSA key ID SOMETHING
If the key ID is not the operator's key ID, the message was signed by someone else. Do not import that key. Do not trust the address inside.
The trust warning
gpg: WARNING: This key is not certified with a trusted signature.
Normal and expected. Ignore. It only means you have not signed the operator key with your own key, which most readers never do.
The expired key warning
gpg: Signature made ... (expired)
Rare. The signing key has expired. Either the operator has to publish a rotation under a fresh signing key (a big event), or the situation is broken. Do not use the address inside until clarified.