He is talking about the Bible is our final authority yes, but a Confession tells you what the Bible actually says. In other words, what do you believe about this book.
A solid confession of faith is a standard. In the Reformed or Particular Baptist community, no one holds the 1689 Second London Baptist Confession of Faith on the same level as scripture. The 1689 works like a public statement or declaration. It is as though like-minded individuals are saying with one voice, "This is what we believe the Bible teaches." To be fair, if a church has a detailed doctrinal statement it is a de facto confession of faith. When my wife and I moved to where we live right now I did my due diligence on churches. I went to dozens of church websites. Many of them had doctrinal statements. Some of the statements were comprehensive and others were brief. These doctrinal statements were helpful because they told me what each church believed, what each church confessed. The statements did not replace scripture, they were a summation of scripture. That is all that a good confession of faith is.