Overview
ChatGPT works fine out of the box — you sign up, you ask a question, you get a reply. But the difference between "fine" and "actually useful" lives in three settings that 90% of new users skip: Custom Instructions, Memory, and your default model. Set them up once, and every future chat starts smarter, sounds more like you, and remembers context across days. In this guide, we'll create your account, walk through those three settings, and finish with a real test prompt that proves the setup works.
Who This Is Useful For
What You Will Build
A fully set-up ChatGPT account that already knows who you are, what you care about, and how you like to be spoken to. By the end of this guide, when you ask ChatGPT something like "draft a quick reply to my landlord about the broken aircon", it will already know your name, your apartment city, and your preferred tone — without you having to say any of that.
What You Need
Step 1: Create Your Account
Go to chatgpt.com and click Sign up. You can use Google, Apple, Microsoft, or email + password. Verify your email and you're in.
You'll land on a clean chat screen with a model dropdown at the top and a message box at the bottom. Resist the urge to start chatting yet — the next 8 minutes of setup will pay off in every chat after this.
Step 2: Pick Free or Paid (For Now, Free Is Fine)
ChatGPT has 6 plans (Free, Go, Plus, Pro, Business, Enterprise) — Article 2 of this series breaks down exactly which one suits you. For setup purposes, start with Free. You'll have GPT-5.5 Instant as your default model, basic Memory, and most everyday features.
Don't pay yet. Use Free for 2–3 days. If you find yourself hitting limits or wanting Deep Research, image generation at scale, or longer context windows, then upgrade — and Article 2 will help you pick the right tier.
Step 3: Fill In Your Custom Instructions (The Setting Everyone Skips)
This is the single most-skipped setting in ChatGPT — and the one that makes the biggest difference.
Click your profile picture (top right or bottom left depending on your device) → Settings → Personalization → Custom Instructions.
You'll see two text boxes:
Most people leave both empty. Don't. Paste in something like this and edit to fit:
What would you like ChatGPT to know about you?My name is [Your Name]. I live in [City, Country].
I work as a [your role / student / freelance designer / retired / etc.].
Things I often need help with:
Writing emails in English and Chinese
Planning trips and weekend activities
Organizing receipts and personal finances
Learning [topic you're studying] Important context:
[Anything else recurring — kids' ages, dietary restrictions,
ongoing projects, the city you commute between]
How would you like ChatGPT to respond?Reply in 繁體中文 unless I write in English first
Be concise — skip the disclaimers and "I'd be happy to help" intros
When you're not sure, ask one short clarifying question instead of guessing
Use bullet points for anything with 3 or more items
When you cite something, link the source
No emojis unless I use one first
Hit Save. From this moment on, every single chat — even brand new ones — will use this context automatically. No more "let me explain my situation again."
Step 4: Turn On Memory — and Check What ChatGPT Has Saved
Memory is the feature that makes ChatGPT feel like it actually knows you over time. With GPT-5.5 Instant (the default model since May 2026), Memory now searches across your past conversations, files, and even Gmail when connected — and ChatGPT shows you exactly which memory it used to generate each answer.
Settings → Personalization → Memory. Make sure the toggle is on.
Below the toggle, you'll see Manage memories — click it. You'll see a list of facts ChatGPT has remembered about you so far. On a brand new account this is empty; after a few weeks of use, it'll have entries like:
You can delete any memory you don't want kept. ChatGPT writes these on its own as you chat — but you can also ask it to remember something specific:
Please remember: I'm allergic to peanuts and tree nuts.
Always mention this when suggesting recipes or restaurants.
ChatGPT will confirm the new memory and reference it forever after.
Step 5: Pick Your Default Model
At the top of any chat, click the model dropdown. With GPT-5.5 you'll see options like:
For now, leave it on Instant. Article 3 of this series covers when to switch — but for setup, the default is the right starting point.
Step 6: Try Your First Real Prompt
Now let's prove the setup works. Open a new chat and paste:
Based on what you know about me from my Custom Instructions
and Memory, suggest 3 small ways I could use you this week
to save time. Keep each suggestion under 2 sentences.
Read the reply. You should notice:
If any of those are off, your Custom Instructions (Step 3) need more detail. Go back, add 2–3 more sentences, and try again.
This 10-second test is also a great way to check whether new info has actually been saved when you add things to memory later.
Going Further
Install the mobile app. ChatGPT on iOS and Android syncs everything — your Custom Instructions, Memory, chat history. Once setup is done on web, it works the same way on your phone.
Try voice mode. Tap the microphone icon (mobile) or headphone icon (web) for a real two-way voice conversation. Great for hands-free use while cooking, commuting, or walking.
Bookmark these 3 things:
Key Takeaways
Here's what you learned in this guide:
You're done. Total time: probably under 10 minutes. Every chat from here on starts smarter than the last one.