lay down a road map

To establish the plan, set of guidelines, course of action, etc., for a particular situation. Luckily, the department head laid down a road map for how to handle these quarterly reports while she is out on maternity leave. It is up to the president to lay a road map for our country's foreign policy in the region. We'll need to lay down a road map for the various updates we plan to implement after the app goes live.