Here are the basic characteristics and features of Lean/Kanban:

• Planning style: Lean/Adaptive
• Delivery Style: Flow/Incremental
• Iteration length: Doesn't have time-boxed iterations
• Principles: Eliminate waste, amplify learning, decide as late as possible, deliver as fast as possible, empower the team, build integrity in, see the whole
• Roles: Not prescribed, existing roles
• Team size: Not prescribed
• Artefacts: Kanban (message board)
• Events: Andon (stop the line), Gemba (go and see)
• Special features: Kaizen (Continuous Improvement), makes work visible, limits work in progress, works with your existing process, makes policies explicit, evolves empirically
• Lacks: A clear process framework of its own; instead it asks that we make our existing process visible and use the principles of Lean to improve it

There are no explicit roles defined by Kanban; assuming you have everyone necessary to do the job you've been asked to do, this is sufficient.

Start with your existing process. Map the workflow on a wall, making it visible so that everyone sees it. Use this sudden wealth of information on how your system works to makes changes and bit by bit evolve it into something that works better.