Inquiry begins in doubt and aims for belief but the rush to get from doubt to belief and achieve mental peace can cause us to short the integrated circuits of inquiry that we need to compute better answers.
For one thing, we sometimes operate under the influence of fixed ideas and hidden assumptions that keep us from seeing the sense of fairly plain advice, and here I would simply recommend reading those versions of the Pragmatic Maxim again and again and trying to triangulate the points to which they point.
For another thing, not everything in logic is an argument. A well-developed formal system will have: (1) Primitives, the undefined terms that acquire meaning from their place in the whole system rather than from explicit definitions, (2) Definitions, that connect derived terms to primitives, (3) Axioms, propositions taken to be true for the sake of the theorems that can be derived from them by means of certain (4) Inference Rules.
But that’s just the formal underpinnings — there’s all sorts of informal heuristics, regulative principles, rules of thumb that go toward sustaining any system of significant practical use, and that’s where bits of practical advice like the Maxim in question come into play.