This Policy Brief is an edited extract from the "FIT Report" that describes what is needed in and for a flexible incentives system to deliver the mitigation potential of terrestrial carbon in developing countries. This Report identifies what needs to be done (the functions), by whom, and in what order, to create and maintain a flow of mitigation and incentives. By identifying the essential or optional elements, we can highlight a path for development and capacity building while policy decisions at the national and international level remain outstanding. This analysis was informed by, but not restricted to, REDD+ initiatives and proposals to date. In addition, precedents and lessons were taken from existing carbon incentive mechanisms and other analogous commodity trades.