Consolidate instructions on CONTRIBUTING.md, and include release process

CONTRIBUTING.md

@@ -21,9 +21,84 @@ Use GitHub Issues page to submit issues, enhancement requests and discuss ideas.
 -  Issues that have been identified as a feature request will be labelled `enhancement`.
 
 
-# Issues
+### Issues
 We use GitHub issues to track public bugs. Please ensure your description is
 clear and has sufficient instructions to be able to reproduce the issue.
 
 # Code of Conduct
 Please follow our [Code of Conduct](CODE_OF_CONDUCT.md).
+
+# Development
+
+## Quick Start
+
+### Prerequisites
+
+See the [Prerequisites section in README.md](./README.md#prerequisites) for complete setup requirements.
+
+### Initial Setup
+
+1. **Clone the repository**
+   ```bash
+   git clone <repository-url>
+   cd datacloud-customcode-python-sdk
+   ```
+
+2. **Set up virtual environment and install dependencies**
+
+   **Note**: If you need to set a specific Python version, use `pyenv local 3.11.x` in the project directory.
+
+   ```bash
+   python3.11 -m venv .venv
+   source .venv/bin/activate
+   pip install poetry
+   make develop
+   ```
+
+3. **Verify installation**
+   ```bash
+   datacustomcode version
+   ```
+
+4. **Initialize a project for development work verification**
+
+   **Note**: To test your changes and develop new features, initialize a sample project:
+
+   ```bash
+   # Create a new directory for your test project
+   mkdir my-test-project
+   cd my-test-project
+
+   # Initialize a new Data Cloud custom code project
+   datacustomcode init .
+
+   # Test your SDK modifications against the sample project with:
+   datacustomcode run ./payload/entrypoint.py
+   ```
+
+   **Tip**: See the [README.md](./README.md) for additional `datacustomcode` commands (`scan`, `deploy`, `zip`) to test specific code paths and validate your SDK changes thoroughly.
+
+## Makefile Commands
+
+```bash
+# Clean build artifacts, caches and temporary files
+make clean
+
+# Build package distribution
+make package
+
+# Install main dependencies only
+make install
+
+# Install dependencies for full development setup
+make develop
+
+# Run code quality checks
+make lint
+
+# Perform static type checking
+make mypy
+
+# Run complete test suite
+make test
+```