Make your first edit
Your first win: a video you can actually post
Take a 30–90 second talking-head clip, cut the mistakes, add readable captions and save the finished MP4. Start with these two prompts. Come back for the extras when that works.
You'll need: a computer with local Codex access, an account that can run it, and one clip. These folder steps use a Mac. On Windows, ask Codex to adapt them before installing anything. Account limits, downloads and rendering time vary.
Open a folder for the job
In Finder, make a folder called video-editing inside Documents, then an inbox folder inside it. Copy one clip into inbox. Keep your original on your phone or wherever you normally save it.
Open that folder in Codex
Choose the local project/folder in the desktop app and start a task there. Need the app? Use the official setup instructions. You need a task that can work with local files and run tools. A chat that only writes instructions cannot export your video.
Copy prompt 1, then prompt 2
Paste each into the same Codex task. Finish the setup check before sending the editing prompt. When Codex asks you to review a cut or preview, reply there.
Already a member? I have full prebuilt video-editing skills inside my membership. See the membership shortcut →
1. Set up once
Codex checks what is installed and makes a five-second test. Open that test and check the picture and sound before continuing. Read what any installation is for before approving it.
2. Make your first edit
Keep the defaults or fill in these details. They update the prompt below. Your answers stay in this page; this form does not upload your video.
No style reference? The prompt uses clear, high-contrast captions. If you have a screenshot you like, attach it in Codex and explain what you like about it.
You are done when: exports/first-edit.mp4 opens and passes the checklist below. The .srt file is a separate, editable copy of the captions.
Check the finished video
“Render” means saving the finished video. Watch the exported MP4 itself, including once on your phone. A good preview does not guarantee a good export.
This checklist is for your current review; ticks reset when you reload.
Feedback that helps
“At 00:12, you cut the first syllable of ‘calendar’. Restore the start of that word.”
“At 00:24, the captions cover the button I'm showing. Move them above the screen recording.”
Keep one approved version
Ask Codex to save the next revision as a new file. That way you can compare it with the edit you already liked.
If you trim anything later, ask it to recheck caption and B-roll timings against the new cut.
Optional: add a hook or closing card
A hook card is text over your opening. A closing card shows the action you want viewers to take. Get the cut and captions working first; then add these if they help. Remotion is useful for reusable animated graphics, and can be added at this stage.
Find your footage again
B-roll is extra footage shown while your voice continues. A screenshot of the calendar you are explaining is B-roll. So is a clip from the workshop you are talking about.
Start with up to 15 assets you already have. Put copies in library: a few clips of you working, a screen recording, useful screenshots and GIFs you are able to use. You can organise the rest later.
| Asset | Description and tags | Useful for |
|---|---|---|
| workshop-room.mp4 | People arriving at a workshop · vertical · 8 seconds | “Here's what happened at the workshop.” |
| calendar-before-after.mp4 | Screen recording of a weekly calendar · landscape · 6 seconds | Showing the actual schedule change |
| waiting.gif | Reaction: waiting · animated · permission to check | A short reaction beat, if cleared for use |
The useful bit is the index. library/INDEX.md is a readable list of what is in each file, where it lives and when to use it. Codex searches that list before opening suitable clips. You should be able to open the list and recognise your own footage.
Copy the library prompt
Keep GIFs moving and originals safe
Check that animations still move in the finished MP4. Use organised copies so renaming a library file does not break an existing project. Convert iPhone footage only when needed, and check skin colour on a short test before processing a whole folder.
Add B-roll that helps
If you say “I gave Claude my calendar”, show the calendar or the result. A logo does not show either of those things.
Use your own library first
Your footage, your workshop, the screen you actually used. Search for the point you are making.
Capture the missing proof
If there is no suitable asset, record or screenshot the real tool. Show just the action the viewer needs to see, with private details removed. If Codex cannot access the app, it should tell you what to capture.
Choose the moments yourself
A GIF can work for a reaction. Stock can work for a generic scene. Both are optional. A clear talking-head video is better than unrelated footage covering it.
A useful B-roll request
“When I say ‘I moved all my meetings to Tuesday’, show the before-and-after calendar. Keep it on screen long enough to read. Leave my voice playing.”
Copy the B-roll prompt
Get unstuck + watch the demos
Open the problem that matches yours and paste the line into the same Codex task. Give it the actual error or filename if you have one.
Codex cannot find my clip
An installation fails or asks for permission
The preview link will not open
The picture looks washed out, orange or stretched
Captions drift or the mouth does not match the audio
The export fails or the file is too large
Something else is wrong
What the tools do
Codex
Works with your files and runs the editing tools. Check access and current setup in the official guide.
App setup →FFmpeg
Handles trimming, joining, conversion and video export. It is free and open source.
Official site →Whisper
Turns speech into text. The local version needs software and model downloads first; timestamps and wording still need checking.
Official project →Remotion · optional
Builds reusable video graphics from code. Add it when you want those graphics. Check its licence for your situation.
Documentation → · Licence →
The guide is free. Codex access and usage limits depend on your account; extra tools or services may have their own charges. The prompts ask before adding anything paid.
Watch my Claude Code + Remotion walkthrough for the graphics workflow. It uses Claude Code, so the app controls and setup steps differ from Codex. Open on YouTube →
Watch: I Stopped Paying for Video Editors. Claude Code Builds Them For Me Now. →
Get the prebuilt skills
I have full prebuilt video-editing skills inside my membership.
If you want the skills already built, you can get them there. A skill is a saved set of instructions your AI can reuse for a particular job.
You can use this free guide to make your first edit, then choose how you want to keep working.
Get the prebuilt skills in the membership →Already a member? Open your membership classroom for the skills.
Prefer to save your own workflow?
After one video passes the final checks, ask Codex to save the process that worked. Test it on a second clip before asking it to edit a whole folder.
Optional: save your process as a skill
Next time: “Use reel-edit on monday-tip.mov in inbox. Show me the proposed cuts and a preview before exporting.” Check that your skill is available first; the official skills guide explains discovery and installation.