The answer is simple: the Trustees named within the Trust documents simply follow the directives set forth in those documents.
Whether that be immediately selling any Trust property and distributing the proceeds as directed by the Trust, or by retaining property (again, as directed by the Trust document) for the benefit of the Trust beneficiaries, the Trust document itself should outline exactly what should occur with the assets of the Trust.
The Trustees do not need any court appointment or supervision, as they merely control the trust assets per the terms of the written trust document and act accordingly.
If the Trustees feel the need for guidance, they can certainly seek the advice of an attorney, but that guidance is not a legal requirement. Find a local attorney for free here.
See this page to create a Living Trust on your own.