# Practice 01 · A repeatable workspace

Work in an extracted copy. Keep the original checkpoint available for comparison. Save a short evidence log with each answer; a screenshot alone does not explain a result.

## A. Trace and change
Start checkpoint 01 using the course's npm scripts. Find the entry HTML, the module entry and the function that supplies the heading. Change the heading to Harbor Together practice desk. Predict which file the browser requests first and explain the roles of Node, Vite, TypeScript and React. Record the local URL and a successful type-check.

## B. Diagnose, then repair
In a separate small .ts experiment included by the project, declare a text variable and assign it a number. Run the type-check. Record the exact error location and explain why a browser build is not a substitute for this check. Repair the type mismatch without any or a type assertion. Remove the temporary experiment afterward.

## C. Transfer
Write a one-page setup note for a classmate who extracts the ZIP tomorrow. Include the working directory, runtime check, dependency installation, dev URL, type-check, shutdown, and one evidence-led troubleshooting step. Explain why node_modules is not part of their authored source. Do not assume that the first printed port is always available.

Completion evidence: three file roles, one changed page, one explained compiler diagnostic, and a reproducible setup note. [Separate worked solutions](../solutions/01.html).