To apply the CMMI framework for software development, you need to go through four steps. First, assess your current situation by understanding your software development processes, their strengths and weaknesses, and their alignment with organizational goals. You can use various methods such as self-assessment, appraisal, or audit to evaluate your current maturity level and identify gaps and opportunities for improvement. Second, plan your improvement strategy by prioritizing improvement goals and selecting relevant and feasible process areas. You should also define roles and responsibilities, resources and tools, milestones and metrics, risks and mitigation strategies for your improvement plan. Third, implement your improvement actions by applying the practices and techniques suggested by the CMMI framework. Communicate, train, and coach staff and stakeholders about the changes and benefits of the new processes. Monitor and control progress by collecting data and feedback. Lastly, evaluate and sustain your improvement results by comparing them with baseline and expected outcomes. Identify lessons learned and best practices to share and reuse. Ensure that results are consistent, sustainable, and scalable by institutionalizing new processes and creating a feedback loop for continuous improvement.