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Installation.md

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+**English** · [Dansk](Installation-da) · [Bahasa Malaysia](Installation-ms)
+
+# Installation
+
+## Requirements
+
+- Python 3.13 or newer with Tkinter. On Debian or Ubuntu install `python3-tk`.
+- `venv` and `pip`, both part of Python.
+- No runtime dependencies.
+
+## Create a local virtual environment
+
+Windows (PowerShell):
+
+```powershell
+python -m venv .venv
+.venv/Scripts/Activate.ps1
+python -m pip install --upgrade pip
+python -m pip install -e ".[dev]"
+```
+
+Linux and macOS:
+
+```bash
+python3 -m venv .venv
+source .venv/bin/activate
+python -m pip install --upgrade pip
+python -m pip install -e ".[dev]"
+```
+
+The `[dev]` extra installs pytest and ruff. Leave it out
+(`python -m pip install -e .`) if you only want to run the program.
+
+## Check the installation
+
+```bash
+python -m pytest
+```