The sustainability agenda needs to be driven by a company's owners directive and clear ownership from executive management. No matter the size of the company.
Sustainability is a broad term. Your company must define sustainability from some perspectives, e.g:
To solve your needs you should approach sustainability the way you approach all business challenges, i.e. approach this as a business case.
To be able to define the business case, executive management/you need to divide sustainability into different areas and set clear objective based on business cases. Only then, you are able to define what and how to prioritize to achieve your ambition to become a more sustainable company.
And to succeed with your sustainable development agenda requires partnerships.
When you choose sustainability partner, the partnership needs to be built upon practical experiences and knowledge, a shared vision, and shared long- and short term objectives that place sustainability and profitability at the centre.