Get started with Codex

Before you start

Have your account sign-in ready and make a folder for practice. Use a copy of a small project, or create a folder called ai-practice with a short notes.txt file. Keep your first task small enough to check yourself.

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1. Install and open your workspace

Follow the official OpenAI quickstart below to download the desktop app for your system and sign in. Current documentation places Codex in the ChatGPT desktop app; an older installation may have different labels.

Open the official download and setup steps ↗

1. Choose Codex in the app’s product selector.
2. Open your practice folder as the project. A project is the folder containing the files for one piece of work.
3. Start a new chat in that project. Check the folder name before you send your task.

2. Ask a question before changing files

Type this example into the chat. It helps you see whether the assistant understands the files you chose.

Explain what is in this folder in beginner-friendly language. Do not change any files. Suggest one small next step.

3. Try one small change

For a folder containing notes.txt, try the example below. Replace the filename if yours is different. A diff is a view of the lines added and removed; read it before accepting the result.

Suggest a clearer structure for notes.txt. Show your proposed text here first and wait for my approval before saving.

1. Read the proposal and ask questions about anything unclear.
2. Approve only the change you want, then inspect the saved file.
3. For code, ask which checks were run and try the result yourself. Keep a backup or use Git, a tool for tracking file history.

4. Use a prompt from this library

Choose a prompt that lists Codex, replace placeholders such as [PROJECT], and paste it into your project chat. Say which files it should use and what should happen before it changes them.

An assistant may be able to edit files or run commands. Read permission requests and avoid sharing passwords or secret keys. A confident answer is not proof that the result is correct.

If you get stuck

If a folder is missing, reopen the intended project. If a feature or sign-in option differs, follow the current official quickstart. For errors, copy the exact message and ask the assistant to explain it before making changes.