Claude Code is the most popular agentic coding tool right now, and in this 2026 update I walk you through the full workflow I actually use to build real-world apps—starting from absolute zero. I show you how to set up Claude Code in the desktop app and the CLI, how to pick the right plan (honestly, Pro is enough to follow along), and how to avoid the API billing trap if you’re an individual because it can get super expensive. From there we cover the fundamentals: attaching files and screenshots, using slash commands, switching modes (ask permissions, auto-accept edits, planning mode, and bypass permissions), plus model selection—Opus for detailed upfront plans, Sonnet for implementation, and Haiku mainly for docs. Then I stop talking theory and we build something you’d actually pay money for: an income and expense tracker with attachments like invoices and receipts, plus dashboards and exports for tax time. I show you how I bootstrap a Next.js starter (React + Drizzle + Postgres + BetterAuth, plus Vercel Blob and the Vercel AI SDK), spin up Postgres with Docker, and use the desktop preview to test auth quickly. The key takeaway is workflow: plan first (ideally with a PRD + clarifying questions), store your plan inside the project, watch your context window, then start a fresh session to implement—starting with a proper UI design system so you don’t end up with generic AI slop.