The first step is to inventory all of the stakeholders and identify internal champions (i.e. people who could advocate the need for DAM).
Internal champions should be from around the organisation and not necessarily just technical staff. They should represent those who are in the most pain under the current practices or workflows, or who have the most to gain from new ones.
In a DAM scenario case, the users with the most at stake are usually marketing managers, creatives, editors, brand managers, agency representatives, sales people, product marketers, licensing staff and other external communicators.