How to Use ChatGPT — A Complete Beginner's Guide
From your first chat to a result you can rely on: Custom Instructions, file uploads, image generation, and when you need a second tool.
Beginner8 min read
What you'll be able to do by the end
- Set up Custom Instructions so you stop repeating the same context in every conversation
- Upload files and images and have ChatGPT work on them — or generate new images from a description
- Use Memory intelligently instead of trusting it blindly
- Know when to turn on web search and when its built-in knowledge is enough
- Avoid the five most common mistakes that make its answers generic or inaccurate
Before you start
- A web browser or the ChatGPT app, plus an email address
- No credit card — the free plan covers everything in this tutorial
ChatGPT from OpenAI was the first conversational AI tool to reach a mass audience, and it’s now the most widely used day to day — for everything from drafting an email to analysing data. Yet most users stick to the default chat without touching Custom Instructions, Memory, or file uploads, and lose more than half the tool’s practical value in doing so.
The difference between an average experience and getting full value isn’t a pricier subscription — it’s knowing about features that already exist in the free plan. This tutorial covers them in the order I’d recommend trying them.
Why ChatGPT specifically
Three things set it apart in practice:
Breadth of features. Image generation, built-in web search, file analysis, and custom GPTs for recurring tasks — all inside one tool, no need to switch apps.
Easy onboarding. A simple interface familiar to almost everyone, and Custom Instructions make the very first answer closer to what you need than with any competitor.
Built-in search. With search enabled, it can pull current information from the web rather than relying only on its training data.
On the other hand, very long documents (over a hundred pages) can get less coherent handling than tools specialised for that. If your core work is analysing huge documents, try both and compare.
The steps
The steps below are ordered the way I’d recommend working through them the first time. Each stands alone, so if you already have some experience, jump to what matters.
Steps
Step 1: Create your account and set Custom Instructions first
Sign in at chat.openai.com or in the app with your email. Before your first conversation, open your account settings and enable "Custom Instructions". There are two fields: who you are and what you do (optional), and how you want answers delivered (tone, length, whether you prefer bullet points or paragraphs). This one step saves you from repeating the same instructions in every new conversation.
Note: Not sure what to write? Try: 'I'm a [your profession]. I prefer direct answers without long preambles, with practical examples.'
Step 2: Pick the right model for the task
Above the message box there's a model selector. Models trade depth against speed: there's a faster one suited to short questions and ordinary conversation, and one that thinks for longer before answering, better for complex tasks like deep analysis or a hard coding problem. Start on the default and move up to the longer-thinking model when answers feel shallow or incomplete.
Note: Tasks with multiple logical steps (math, debugging code, project planning) benefit most from the longer-thinking model, even if it's slightly slower.
Step 3: Upload files and images instead of copy-pasting
Click the attachment icon next to the message box and upload a PDF, Word doc, Excel sheet, or image. ChatGPT reads the file's contents and can summarise it, extract data from it, or compare several files. For images, it can describe them or pull text out of them. Beginners often skip this feature and paste long text that loses its formatting instead.
Note: If you want a brand-new image rather than analysis of an existing one, just ask directly: 'Generate an image of...' and describe the details — size, style, colours.
Step 4: Understand the difference between Memory and Custom Instructions
Memory lets ChatGPT recall details from previous conversations automatically — your project name, recurring preferences. Custom Instructions are fixed and written by you explicitly. The difference matters: Memory accumulates on its own and may store things you didn't intend to save, so review it periodically in settings and delete anything inaccurate or sensitive.
Note: Want a truly 'clean' conversation unaffected by accumulated memory? You can pause memory temporarily in settings for that session.
Step 5: Turn on web search for anything time-sensitive
If your question needs current information — today's price, this week's news, a tool's latest release — enable web search from the message box instead of relying on its internal knowledge, which has a cutoff date. Without it, the answer is based purely on training data and may be out of date.
Note: Even with search enabled, verify any important figure or source yourself before using it in a decision or a post.
Common mistakes — and how to avoid them
MistakeAsking a one-line question and expecting accurate, ready-to-use output: 'write me a marketing plan'.
Do this insteadSpecify the audience, rough budget, and timeframe. Every detail you add cuts down the number of attempts you'll need.
MistakeTrusting Memory completely and assuming it remembers everything accurately.
Do this insteadFor important, recurring information, put it in Custom Instructions explicitly rather than relying on what it stores automatically.
MistakeAsking about a current price or statistic without enabling web search.
Do this insteadEnable search for any time-sensitive question, otherwise the answer is built on stale training data.
MistakeOpening a new conversation every time you want to tweak one small detail on the same topic.
Do this insteadContinue in the same thread and edit your earlier message — accumulated context improves every subsequent answer.
MistakeBelieving any number or reference it mentions and dropping it straight into a report or post.
Do this insteadTreat every figure and source name as a draft to be verified against the original.
❓ Frequently asked questions
Is ChatGPT actually free?
There's a free plan that covers most daily use, with a usage cap on the strongest model that refreshes periodically. Advanced features like building custom GPTs or higher usage limits are reserved for paid plans.
What's the practical difference from Claude?
ChatGPT is broader in extras — image generation, built-in search, plugins, custom GPTs — while Claude is usually stronger at long-document analysis and natural writing. If your work is varied and needs extra capabilities, ChatGPT is the more practical choice.
Are my conversations used to train the model?
There's an explicit account setting that controls this ('improve the model for everyone'). Check it yourself in settings, and never upload sensitive data to any AI tool regardless of its stated policy.
When should I use the longer-thinking model?
For tasks with multiple logical steps: complex debugging, data analysis, multi-stage planning. For quick questions and ordinary conversation, the faster model is enough and conserves your free usage limit.