Playbook
Build a Custom GPT for your business
ChatGPT · 20 min · Published April 2, 2026
Why this matters
Your customers ask the same 20 questions over and over. Your team spends hours answering them. A Custom GPT trained on your FAQ, product docs, and brand voice can handle these instantly — and it sounds like you, not a robot.
This isn't basic ChatGPT. You'll set up custom instructions, upload knowledge files, and configure the GPT to stay on-brand. The result: a branded AI assistant that lives inside ChatGPT.
What you'll build
✓ A Custom GPT with your brand personality
✓ Uploaded knowledge base (FAQ, product docs)
✓ Custom instructions that keep it on-topic
✓ Shareable link for your team or customers
Step-by-step
Define your GPT's personality
Write 2-3 sentences describing how your GPT should communicate. Example: 'You are a friendly customer support agent for Ember & Co, a handmade candle brand. Be warm but concise. Never make up product details — if unsure, say so.'
Prepare your knowledge files
Gather your FAQ document, product catalog, return policy, and any brand guidelines. Upload these as knowledge files when creating the GPT.
Knowledge
Upload files your GPT can reference
Drop files here or click to upload
FAQ.pdf
24 KB
product-catalog.csv
156 KB
brand-voice-guide.md
8 KB
✓ 3 files uploaded successfully
Set conversation starters
Add 3-4 suggested prompts that guide users: 'What's your most popular candle?', 'Do you ship internationally?', 'What's your return policy?'
Ember Support Agent
Ask me anything about our candles, shipping, or returns
Test and refine
Ask it questions a real customer would ask. Look for hallucinations, off-brand responses, or gaps. Tighten the instructions until it stays reliable.
Try it yourself
Copy this starter prompt into a Custom GPT’s instructions field. Replace the placeholder with your business name and customize from there.
You are a friendly customer support agent for [Your Business Name]. Your job is to answer customer questions accurately and warmly. - Use a conversational, helpful tone - Never make up product details — if you're unsure, say so - Keep answers concise (2-3 sentences when possible) - Suggest related products when appropriate - Always end with an offer to help further