# The chat interface, briefly

Web page: https://academy.memberpress.ai/courses/desktop-fundamentals/l2/

Lesson 2 of 9 in [Claude Desktop Fundamentals](https://academy.memberpress.ai/courses/desktop-fundamentals/), 5 min.

Video: https://www.youtube.com/watch?v=JmiOw7D25oQ

The interface has more controls than a first glance suggests. Knowing where each one lives saves you from hunting mid-conversation when you need it.

**What each element does**

The model picker sits in the top-left of the chat input bar. It controls which Claude version handles your message. For most daily work, the default is fine. Switch to Opus when you need the model to hold a longer reasoning chain or handle a complex multi-step task; switch to Haiku when you need fast, cheap responses for high-volume work.

The attachment button (the paperclip icon) opens a file picker. You can also drag files directly into the chat window. Supported types include PDF, DOCX, TXT, images (PNG, JPG), and CSV. What the model can do with a file depends on the file type — it can read text from a PDF but cannot execute an Excel macro.

The "new chat" button (the pencil icon, top-right) starts a blank conversation with no memory of prior threads. Each chat is independent unless you are inside a Project, which carries persistent context.

The sidebar lists your recent chats. Starred chats pin to the top. You cannot rename a chat after the fact, so if you care about finding a thread later, star it immediately.

**Walk-through**

Open a new chat. Send one message — anything. Then:

1. Click the model picker and note the options available on your plan.
2. Drag a small text file into the chat window. Confirm the attachment thumbnail appears.
3. Star the chat using the star icon in the sidebar.
4. Click "new chat" and confirm the previous conversation is gone from the input area (it still exists in the sidebar).

**If you get stuck**

- "I do not see the model picker" — It appears only after you click inside the input field on some versions. Click the text area first.
- "My file attachment disappears after I send the message" — The attachment is embedded in the message. Scroll up; it is still there, just not shown in the input bar again.
- "I cannot find the chat I just had" — It is in the sidebar. If the sidebar is hidden, click the hamburger icon (three lines) in the top-left to expand it.

**Cross-reference**

When you are ready to give a chat persistent memory across sessions, see "Save what works as a Project" — that lesson turns a throwaway chat into a reusable workspace.

**Deliverable**

You have used the model picker, attached a file, starred a chat, and started a new one. The starred chat is visible at the top of your sidebar. That is the observable success criterion.

## Try these prompts

- I attached a PDF to a chat and now I can't find it after sending my message. What happened and where is it?
- What is the difference between the Haiku and Opus models in the model picker, and when should I switch from the default?
- I want to keep a specific chat thread easy to find later. What should I do inside Claude Desktop right now?

Next: [Your first useful query](https://academy.memberpress.ai/courses/desktop-fundamentals/l3/)