Quick start
From opening Codex to shipping a small tool — only the steps that matter.
Chapter 1 — What Codex is
Think of Codex as a coding partner. You explain the business goal clearly; the rest is on Codex.
The more clearly you describe what you want, the closer the first version will be to your vision.
This tutorial covers desktop tools only: Windows / macOS. Double-click to open when done.
Chapter 2 — What you need
A Windows or macOS computer
Windows 10/11 or a recent macOS. 8 GB RAM is the minimum; 16 GB is more comfortable.
A ChatGPT account
Just sign in with your ChatGPT account.
The Codex Desktop installer
Download from the OpenAI site and double-click to install.
No technical background needed
If you can describe the workflow and judge whether the result is right, that's enough.
Chapter 3 — Opening Codex for the first time
You'll sign in on first launch and land in a chat-style interface.
Left: tasks. Center: conversation. Right: file preview.
Just remember three moves: new task, paste a prompt, wait for the result.
Chapter 4 — Core actions in plain English
New task = new conversation
One goal = one conversation. Don't mix several things in one thread.
Prompt = what you tell Codex
Describe the input, the output, and what the screen looks like. Don't just say "build a tool."
Wait = let it work
Ignore the technical details while it's working. Just check whether the app runs in the end.
Run = see your app
When it finishes, a window pops up — that's your tool.
Not right? = keep talking
If something's off, just say so. Like "the button color is wrong" or "import crashes the app." Codex will fix it.
Chapter 5 — Five rules for great prompts
1. Say who will use it
The user shapes the interface and the workflow.
2. Say what problem it solves
Don't just list features — describe the pain you want to remove.
3. Give examples
"Order ID, Amount, Date — group by month" beats "build me some stats" by a mile.
4. Change one thing at a time
One change per request. Much higher success rate.
5. Don't panic on errors
Copy the full error back to Codex and let it diagnose and fix itself.
Chapter 6 — Common issues
Issue 1 — The app won't start
Copy the full error and ask: "How do I fix this?"
Issue 2 — Things get messier with each tweak
If several fixes in a row don't help, start a new task and describe the need fresh.
Issue 3 — Too much too soon
Start small: import one sheet, show one column. Once that works, add features.
Issue 4 — You can't tell what it's doing
Just ask: "What are you doing right now?"
Chapter 7 — When to stop
Stop once the artifact is real
When the app opens, sample data runs through, and a file exports — pause feature work.
Don't force the same bug forever
If the same issue resists three fixes, ask Codex to disable the edge feature and keep the main flow.
Save new ideas for v2
Write extra ideas into a v2 list instead of turning version one into an endless project.
Big changes deserve a new task
Once the main flow works, use a fresh task for redesigns, stack swaps, or piles of new features.