Barth is elusive--not intentionally--but elusive all the same. That's all.
Section 1 - The Task of Dogmatics
Barth is, of course, a presuppositionalist. With regards to dogmatic inquiry and theological work, Barth demands that dogmatics be an act of faith. "Dogmatics is part of the work of human knowledge...Like all serious work of human knowledge, it demands the best will to utilize these faculties [of attentiveness and concentration]...Over and above this, however, it demands faith" (p. 17). For Barth, faith requires, among other things, being called out (p. 17). Being called out includes being called into the Church. Barth presupposed the existence, or the reality therein, of the church. He has not yet defined what exactly makes the church the church (not yet fully at least), but he does give us a hint in the open paragraph.
The Church confesses God as it talk about God. It does so first by its existence in the action of each individual believer. And it does so secondly by its specific action in fellowship, in proclamation by preaching and in the administration of the sacraments, in worship, in its internal and external mission including works of love amongst the sick, the weak and those in jeopardy (p. 3).Assuming he will go on to define the church in a more detail manner (perhaps Church vs. church?) and unpack some of the specifics a bit more (i.e. what is a sacrament?, what is preaching?, etc.) this definition should suffice for the time being and is a wonderful summation of what I would call the church.
In this brief section, Barth outlines how dogmatics might be comparable to say, physics or biology. That is to say any serious scientific inquiry. How you might ask? These three have in common a general desire to discover the truth about something. Physics about energy and movement, biology about life, and dogmatics about God. While the church talks about God in almost all speech (Barth argues all speech) not everything they say is actually correct! So, just as in physics and chemistry there must be criterion for evaluating what is said about God, and these criterion can be found in the person of Jesus.
How does dogmatics fit into the scheme of biblical interpretation? "...Dogmatics as such does not ask what the apostles and prophets said, but what we must say on the basis of the apostles and prophets" (p. 16).