The notion that there is "a plain sense" of Scripture, and correlatively that Scripture alone should govern our life in Communion, is mistaken. It is belied by the existence of many thousands of Protestant denominations, all of which have their origin in disagreements over what Scripture says.
Rather, as Paul told Timothy, the Church is the pillar and foundation of the Truth. The Lord gave the Apostles magisterial (magister = teacher) and juridical authority, which they passed on to their successors, and which they passed on to their successors -- a process that will continue until the Lord returns in glory. It is the bishops of the Church, as successors of the Apostles, who have authority to interpret Scripture and promulgate doctrine (docere = to teach).
We may, of course, interpret it too, but only within the parameters of their interpretation.