Adjusting to new rules is a common problem for stepfamilies. Your stepparent may have different opinions and expectations.
Your stepparent may have some rules that you like better.
If you don't like a particular rule, it probably won't help to tell your stepparent that it is a bad rule. It may be helpful to tell your stepparent that the rule is different, and you are having trouble adjusting to it. Try to work out rules on which both you and your stepparent can agree.