diff --git a/readme.md b/readme.md
index 35e41a1..143c21a 100644
--- a/readme.md
+++ b/readme.md
@@ -1,14 +1,29 @@
-## Windows (.exe)
+# Bio-Impedance Amplifier | Executables
+This repository contains compiled Rust-based software for communicating with a custom-built bio-impedance amplifier.
+
+## Features
+- Single-frequency and frequency-sweep measurements
+- Real-time visualization of magnitude and phase
+- Support for both 2-lead and 4-lead measurements
+- Data logging to `.csv` files
+- Day and night display modes
+- Control via on-screen buttons or keyboard shortcuts
+- Adding custom markers at specific timepoints
+
+## Installation
+This software supports Windows and macOS; Linux distributions are available on request.
+
+### Windows (.exe)
 
 1. Run `Bio-Z App Windows.exe`.
 
-## macOS
+### macOS
 
 Additional steps are required on macOS. Otherwise, you may see a message such as
 *"This app can’t be opened because it is from an unidentified developer."*
 You can choose one of the following options:
 
-### Option 1: Use the native binary (no extension)
+#### Option 1: Use the native binary (no extension)
 
 1. Open `Bio-Z App macOS 1`.
 2. A warning will appear stating that `Bio-Z App macOS 1` cannot be opened.
@@ -16,7 +31,7 @@ You can choose one of the following options:
 4. Scroll down and click **Open Anyway** under **Security**.
 5. Follow the onscreen instructions.
 
-### Option 2: Use the application bundle (.app)
+#### Option 2: Use the application bundle (.app)
 
 1. Open **Terminal** and navigate to this folder using `cd`.
 2. Run the following command to remove the quarantine attribute:
@@ -24,4 +39,45 @@ You can choose one of the following options:
    ```bash
    sudo xattr -cr Bio-Z\ App\ macOS\ 2.app
    ```
-3. Open `Bio-Z App macOS 2`.
\ No newline at end of file
+3. Open `Bio-Z App macOS 2`.
+
+## `.csv` output format
+### File Naming
+- Output filenames are automatically adjusted.
+- Files end with either:
+  - `_single.csv` for single measurements
+  - `_sweep.csv` for sweep measurements
+- Single and sweep data are **never combined** in one output file.
+
+### Marker Functionality
+- A new feature **Add marker** is available during a measurement.
+- Activating **Add marker** opens a popup:
+  - Can be triggered via button or shortcut key **A**
+- Entered text is saved as a **marker** in the CSV output.
+- Markers can later be detected and used in data analysis.
+
+### Time Reference
+- Time values are expressed in **milliseconds (ms)**.
+- Time starts from the moment the hardware is powered on or connected via USB.
+
+### CSV Column Structure
+#### Single Measurement (`*_single.csv`)
+Column number | Parameter | Description |
+---|------|-------------|
+1| Time (ms) | Time since hardware power-on |
+2| Frequency | Measured frequency |
+3| Magnitude | Signal magnitude |
+4| Phase | Signal phase |
+5| Marker | User-defined marker text |
+
+#### Sweep Measurement (`*_sweep.csv`)
+Column number | Parameter | Description |
+---|------|-------------|
+1| Time (ms) | Time since hardware power-on |
+2| Frequency | Measured frequency |
+3| Magnitude | Signal magnitude |
+4| Phase | Signal phase |
+5| Index / Measurement number | Sweep index |
+6| Marker | User-defined marker text |
+
+