A Document-Thinking Teaching Framework for LaTeX: Why Syntax Belongs in the Appendix

LaTeX is conventionally taught as a markup language whose primary content is the syntax of commands, environments, packages, and parameters. Vietnamese-language LaTeX instruction inherited this orientation from international templates, including the canonical Vietnamese baseline (Nguyễn Thái Sơn 2010). The result is a documented failure mode in which learners can typeset a single sample document but cannot author a new one without re-typing the sample, cannot debug their own structure, and cannot transfer skill across document classes. This paper argues that the failure mode is structural: it is caused by foregrounding syntax — which is extraneous cognitive load in the Sweller sense — at the moment the learner has not yet acquired the document-thinking primitives that syntax serves. We synthesise the LaTeX literature (Lamport 1986/1994; Knuth 1984; Mittelbach et al. 2023 The LaTeX Companion 3e; Goossens et al. 2007; Oetiker et al. 2024; the l3kernel/expl3, KOMAScript, and memoir documentation) with cognitive-load theory (Sweller, van Merriënboer, Paas 2019) and desirable-difficulty pedagogy (Bjork & Bjork 2011) to derive a three-layer thinking framework. Layer 1 (document-thinking): structural sectioning, cross-references, semantic markup, bibliography integration, output-target awareness. Layer 2 (presentation-thinking): typography, spacing, page layout, math composition, figure placement. Layer 3 (automation-thinking): macros, conditionals, package customisation, custom-class development. Layers 1 and 2 are the spine of learner mastery and constitute the body of Vol 3. Layer 3 is the cluster and is treated as a single survey chapter pointing at The LaTeX Companion and l3kernel documentation rather than as a programming course inside the textbook. Syntax is repositioned as appendix-level reference material indexed against the thinking primitives that demand it. The framework derives a Vol 3 chapter outline of seven body chapters plus a syntax appendix, deliberately mismatched against the syntax-organised structure of the Vietnamese 2010 baseline. Beamer is out of scope (deferred to H4.3); modernised tooling is out of scope (deferred to H4.2).