How to onboard a part-time developer efficiently without losing context?

1. Prepare a concise overview of the codebase - including architecture diagram, tech stack summary, and known issues - before the developer begins. 2. Record a short asynchronous walkthrough video of the product and key workflows. 3. Grant access to documentation, repositories, and staging environments on day one. 4. Assign a small, isolated initial task to help build familiarity before independent work starts. 5. Schedule a 30-minute sync during week one to answer questions and agree on communication preferences.