How to correct data added in error to steps activity

Go to Apple Health app on the phone tap on Browse at the bottom then tap Activity then tap on Exercise Minutes scroll to the bottom and select Show all data then tap on the date that you want to remove then tap on edit in the top right corner then tap on the red minus sign of each minute and delete the one's you don't want,when you're finished tap on done in the top right corner.

Delete it from where you added it.