規則 and 約束: rules and promises
Distinguish shared rules from commitments made with someone.
A shared rule
規則 (きそく) refers to rules established for a group or activity. 「図書館の規則を読みました」 says that the speaker read the library rules.
「規則に従って利用します」 means using something in accordance with the rules. It does not mean personally setting those rules; distinguish creation from compliance.
A commitment to someone
約束 (やくそく) is a commitment about what one will do or keep. 「秘密を話さないと約束しました」 means promising not to reveal a secret. It is not limited to an appointment.
「約束を破ってしまいました」 means breaking a promise. It is a figurative combination for failing to keep a commitment, not physically tearing an object.
Why and where it applies
「規則ではありませんが、約束なので守ります」 means keeping something because it is a promise, though not a rule. It contrasts a group rule with a personal commitment.
「規則を確認してから約束しました」 means checking the rules and then making a promise. They are two separate completed actions.
Does 「規則を守りました」 mean creating a new rule?
Show the answer and why
No. It means following the rules. Creating them can be expressed as 「規則を作る」.