---
title: Quick start
nav: Quick start
order: 1
description: From opening a folder to hitting Ctrl+S and overwriting the original file — the whole flow in five steps.
updated: 2026-08-12
---

## 1. Open the editor

Go to <https://fish-zero.com/MDEditor> and you are in. Nothing to install, nothing to sign up for,
and you can start typing before you have read any of this.

For the full experience — opening a folder and overwriting files in place — use a Chromium-based
browser: Chrome, Edge, Brave, or Arc. Firefox and Safari can edit and preview, but saving falls back to a download.

## 2. Pick a folder

In the **Files** sidebar, press **📂 Choose folder** and select a folder that contains `.md` files.
The browser will ask you to grant access. After that, every `.md` in the folder (including subfolders)
is listed in the sidebar — one click loads it.

- With many files, the search box filters by file name; `Ctrl+P` expands the sidebar and jumps straight into it.
- `.. Parent` walks one directory up.
- You don't have to open a folder at all: **drop a single `.md` file** onto the window.

> Next time you come back, the sidebar shows **📂 Reopen: your last folder**. One click takes you back —
> but the browser will still ask for permission again. That is the browser's security model, not the editor forgetting.

## 3. Write, and watch the right-hand side

The left pane is the editor with line numbers, the right is the live preview. The toolbar buttons
insert syntax rather than hiding it:

| Button | What it inserts |
| --- | --- |
| Heading (dropdown) | `# ` through `###### ` |
| Bold / Italic | `**text**` / `*text*` |
| Underline | `<u>text</u>` (Markdown has no underline syntax) |
| Strikethrough | `~~text~~` |
| Divider | `---` |
| Code block | a fence line before and after (three backticks) |
| Link (dropdown) | text link, URL link, image |
| Table | asks how many columns, then writes the header and separator rows |

Every code block in the preview gets a **Copy** button in its top-right corner. Scroll down a little
and a **Back to top** button appears in the bottom-right.

## 4. Save

`Ctrl+S` (or **Save**, the green button in the toolbar) **overwrites the file you opened**. No trip through the
Downloads folder, no manual replace.

- **Save As** lets you choose a new location and name.
- **Copy MD** (floating in the top-right corner of the editor pane) puts the whole source on your clipboard.
- If the status bar says *Cannot overwrite in place — use Save As*, this file came without write
  permission (dropped files usually do). Use Save As instead.

## 5. Shape the view

- **Toggle sidebar** — collapse the file list for a wider editor.
- **Show / hide editor** — preview only, i.e. reading mode.
- **Side-by-side dual preview** — a second preview for another document; see [dual preview](/en/MDEditor/docs/dual-preview).
- **Themes** — the three icon buttons in the top-right (moon / sun / leaf): dark, light, warm sepia. Hover for the name.
- **Language** — the globe pill in the top-right corner: Traditional Chinese, English, Japanese.
- **Fullscreen** and **Print** — printing outputs the preview only, never the toolbar.

Whether the sidebar and editor pane are open, plus your theme and language, are remembered in your
browser. Next visit looks the way you left it.