Add building instructions

Author: psonnera

README.md

@@ -15,3 +15,101 @@ The current build logs of the documentation can be found in [Github Actions](htt
 ### Broken links
 
 Detail of broken links in the doc can be found in the build logs. Select a build in Github Action "Deploy", then "Usage". Click on "build" and expand again the "Build line". Search for "WARNING".
+
+## Building Documentation Locally
+
+You can build the documentation locally on your computer to preview changes before committing them.
+
+### Prerequisites
+
+Ensure Python 3.8+ is installed on your system. Install the required dependencies from the root of the repository:
+
+```console
+pip install -r requirements.txt
+```
+
+### Building
+
+Build the English documentation:
+
+```console
+cd docs/EN
+sphinx-build -M html . _build
+```
+
+The built documentation will be in `docs/EN/_build/html/`. Open `index.html` in your browser to view it.
+
+To build a different language (e.g., Czech):
+
+```console
+cd docs/CROWDIN/cs
+sphinx-build -M html . _build
+```
+
+## Quality Check Utility
+
+The `qualitycheck.py` script in the `utils/` folder validates the documentation for common issues like broken links, missing images, and orphaned files.
+
+### Basic Usage
+
+Check the English documentation:
+
+```console
+python utils/qualitycheck.py
+```
+
+Check a specific language (e.g., Czech):
+
+```console
+python utils/qualitycheck.py --lang cs
+```
+
+Check all languages (English + all CROWDIN translations):
+
+```console
+python utils/qualitycheck.py --lang all
+```
+
+### Available Options
+
+- `--lang <code>` - Language selector (default: `EN`). Use CROWDIN language codes like `cs`, `de`, `fr`, or `all` for all languages.
+
+- `--docs-root <path>` - Docs root folder (default: `docs`).
+
+- `--check-remote-links` - Also validate non-image remote links (http/https). This enables checking that external links are accessible.
+
+- `--fail-on-unused` - Fail (exit with non-zero code) if unused pictures are found. Useful for CI/CD pipelines.
+
+- `--timeout <seconds>` - HTTP timeout in seconds for remote checks (default: 8). Increase if checking remote links on slow connections.
+
+- `--workers <number>` - Number of parallel workers for remote checks (default: 12). Adjust based on your system resources.
+
+### Checks Performed
+
+The utility performs the following validations:
+
+1. **Broken anchors and reference calls** - Detects invalid anchor links and references within the documentation.
+2. **Broken local links** - Finds links to non-existent local files.
+3. **Missing pictures** - Identifies image references that point to non-existent files.
+4. **Remote pictures** - Validates that remote images are accessible (when `--check-remote-links` is used).
+5. **Unused pictures** - Detects image files that are not referenced anywhere in the documentation.
+
+### Examples
+
+Validate English docs with all remote checks:
+
+```console
+python utils/qualitycheck.py --check-remote-links
+```
+
+Validate Czech docs and fail if unused images are found:
+
+```console
+python utils/qualitycheck.py --lang cs --fail-on-unused
+```
+
+Validate all languages with increased timeout and worker count:
+
+```console
+python utils/qualitycheck.py --lang all --check-remote-links --timeout 15 --workers 20
+```

utils/readme.md

@@ -38,11 +38,24 @@ https://docs.readthedocs.io/en/stable/api/v3.html#token
 $ python importRedirects.py <APIKEY>
 ```
 
-### Import Redirects
+### Delete All Redirects
 
 This script removes all redirect from the project. The script could be used for testing or maintenance.
 **NOTE: this script will remove all redirects, including the ones that are manual added trough the GUI.
 
 ``` console
 $ python deleteAllRedirects.py <APIKEY>
 ```
+
+## Building Documentation Locally
+
+You can build the documentation locally on your computer to preview changes before committing them.
+
+### Prerequisites
+
+First, ensure Python 3.8+ is installed on your system. Then install the required dependencies from the root of the repository.
+
+### Python Environment
+
+1. **Create a virtual environment** (recommended):
+