docs: make the contribution rules clearer

CONTRIBUTING.md

@@ -63,6 +63,37 @@ Please follow these coding conventions as we do when writing code for Scrapling:
 > Please don’t put your name in the code you contribute; git provides enough metadata to identify the author of the code.
 
 ## Development
+
+### Getting started
+
+1. Fork the repository and clone your fork:
+   ```bash
+   git clone https://github.com/<your-username>/Scrapling.git
+   cd Scrapling
+   git checkout dev
+   ```
+
+2. Create a virtual environment and install dependencies:
+   ```bash
+   python -m venv .venv
+   source .venv/bin/activate  # On Windows: .venv\Scripts\activate
+   pip install -e ".[all]"
+   pip install -r tests/requirements.txt
+   ```
+
+3. Install browser dependencies:
+   ```bash
+   scrapling install
+   ```
+
+4. Set up pre-commit hooks:
+   ```bash
+   pip install pre-commit
+   pre-commit install
+   ```
+
+### Tips
+
 Setting the scrapling logging level to `debug` makes it easier to know what's happening in the background.
 ```python
 import logging
@@ -73,15 +104,6 @@ Bonus: You can install the beta of the upcoming update from the dev branch as fo
 pip3 install git+https://github.com/D4Vinci/Scrapling.git@dev
 ```
 
-## Building Documentation
-Documentation is built using [Zensical](https://zensical.org/). You can build it locally using the following commands:
-```bash
-pip install zensical
-pip install -r docs/requirements.txt
-zensical build --clean  # Build the static site
-zensical serve          # Local preview
-```
-
 ## Tests
 Scrapling includes a comprehensive test suite that can be executed with pytest. However, first, you need to install all libraries and `pytest-plugins` listed in `tests/requirements.txt`. Then, running the tests will result in an output like this:
    ```bash
@@ -100,9 +122,27 @@ Scrapling includes a comprehensive test suite that can be executed with pytest.
 
    =============================== 271 passed in 52.68s ==============================
    ```
-Hence, we used `-n auto` in the command above to run tests in threads to increase speed.
+Here, `-n auto` runs tests in parallel across multiple processes to increase speed.
+
+**Note:** You may need to run browser tests sequentially (`DynamicFetcher`/`StealthyFetcher`) to avoid conflicts. To run non-browser tests in parallel and browser tests separately:
+```bash
+# Non-browser tests (parallel)
+pytest tests/ -k "not (DynamicFetcher or StealthyFetcher)" -n auto
+
+# Browser tests (sequential)
+pytest tests/ -k "DynamicFetcher or StealthyFetcher"
+```
 
 Bonus: You can also see the test coverage with the `pytest` plugin below
 ```bash
 pytest --cov=scrapling tests/
 ```
+
+## Building Documentation
+Documentation is built using [Zensical](https://zensical.org/). You can build it locally using the following commands:
+```bash
+pip install zensical
+pip install -r docs/requirements.txt
+zensical build --clean  # Build the static site
+zensical serve          # Local preview
+```