Run your URL against the validator tool to test. If you are working with a Player Card, request approval for whitelisting. All other Cards do not need whitelisting.
After testing in the validator or approval of your Player Card, Tweet the URL and see the Card appear below your tweet in the details view.
Use Twitter Card analytics to measure your results.
日本語翻訳文のステップ3の説明に、重要な説明が漏れています: If you are working with a Player Card, request approval for whitelisting. All other Cards do not need whitelisting.