The governance of not-for-profits is undertaken by the board or committee (these terms can be used interchangably). The governance of an organisation is different to the everyday work of the organisation. Boards and committees make strategic decisions and management and staff/volunteers then action the governance decisions (for more information see the page Who runs the organisation?).
Decisions made by board and committees can include setting strategic directions, hiring staff, whether or not to take disciplinary action against a member, which contractors or service-providers to engage, and what activities to undertake.
Good governance means complying with the law and legal duties, and carrying out the governance role in the best interests of the not-for-profit. There are considerations beyond strict legal duties when thinking about good governance, such as how meetings are held, who is on your board and what skills they have, how new committee members are inducted, how frequently the board meets, how board papers are prepared and distributed and more. There are many online tools and resources available to groups to help them improve their governance.