Social capital covers the key concepts that are the basis for optimal collaboration. So it is not a new playbook or yet another new management concept. Social capital is a special perspective on management – a way of understanding, measuring and talking about what an organization can achieve through good relationships and good cooperation.
If you want to focus on your social capital, you can start with "The world's shortest questionnaire". It's just 4 questions for the employees about how they experience trust and fairness. This is a good "temperature measurement", which gives a good picture of where in the organization there is a particular need to invest.