"the ministry of condemnation." This refers to the Old Testament law. Alternate translation: "the ministry that condemns people because it is based on the law"
Paul speaks of "the ministry of righteousness" as if it were an object that could produce or multiply another object. He means that "the ministry of righteousness" is far more glorious than the law, which also had glory.
This refers to the new covenant, of which Paul is a minister. Alternate translation: "the ministry that makes people righteous because it is based on the Spirit"