Complete guide to ChatGPT

Getting started

Go to chatgpt.com and create a free account with email or Google. When it opens, a new chat is already waiting for you: type your first question or instruction (called a "prompt") in the text box. You can type text, but you can also attach an image, an audio file or a document for it to analyze. You don't need to configure anything to get started: the more specific you are about what you ask for (what you want, for whom, in what format), the better the response will be. If the first response isn't exactly what you were looking for, keep the conversation going by asking for adjustments instead of rephrasing from scratch: ChatGPT keeps the context of the whole chat.

Use cases

Advanced setup

1. Custom instructions
   In Settings → Personalization, fill in what ChatGPT should know about you (your role, your level, your goal) and how you prefer responses (tone, length, format). They apply automatically to all new conversations. Limit: 1,500 characters per field.
2. Memory
   Unlike custom instructions (fixed), memory learns details over time: your name, your projects, your preferences shown in past conversations. Turn it on in Settings → Personalization → Memory, and you can review or delete what it remembers at any time.
3. Projects
   Groups conversations on the same topic, with files and instructions shared across all the chats in that project. Useful if you work continuously on something specific (a thesis, a product, a client) and don't want to repeat context every time.
4. Choosing the right model
   GPT-5.5 Instant is fast and free, designed for everyday use. Reasoning models (o3, o4-mini) take longer but think step by step, which makes them better for math or complex problems. Switch models from the selector at the top depending on the task.

Tips

• Tell ChatGPT what you DON'T want, not just what you do want: "don't use bullet lists" or "avoid corporate language" improves the result far more than giving only positive instructions.
• Use the PTCF framework (Persona, Task, Context, Format) when writing a prompt: tell it who it should be, what it needs to do, with what context, and in what format you want the response.
• If you need to keep a fixed style or set of rules across many conversations, put them in Custom instructions instead of repeating them every time.
• For tasks that require a lot of thinking (math, logic, complex code), switch to the reasoning model instead of the fast default model.
• When you upload a long document, ask for a general summary first before asking specific questions: it helps make later answers more accurate.

FAQ