The Training for the Digital Battlefield program, also known as the Close Combat Tactical Trainer-Digital (CCTT-D) project, was conducted by the U.S. Army Research Institute (ARI) Armored Forces Research Unit (AFRU) located at Fort Knox, Kentucky. The ARI's research on training requirements and evaluation methods is supported by a Memorandum of Agreement between the U.S. Army Armor Center and ARI entitled Manpower, Personnel, and Training Research, Development, Test, and Evaluation for the Mounted Forces, 16 October 1995. This report describes one of tile Army's latest efforts to address the changing training requirements driven by advances in warfighter technologies. The modification of training delivery systems and training programs to incorporate the unique requirements brought about by digital warfighting technologies moves the Army closer to meeting the training challenges of battlefield digitization. The current research effort, tile Training for the Digital Battlefield program, also known as the Close Combat Tactical Trainer-Digital (CCFT-D), was designed to ascertain the anticipated requirements associated with using the CCTT (or a similar training delivery system) to conduct training for digitally-equipped platoon through brigade units. The requirements analysis was twofold. First, it focused on technology capabilities; tactics, techniques, and procedures; scenario design and development; and tile structure of training materials specific to the CCTT. Second, it provided a training approach and an analysis of technology requirements that encompass the entire Army. This report spans two volumes. Volume I presents tile methods and products of tile research effort, featuring an overarching training approach and a training system analysis for delivering digital operations training to Force XXI. Volume II presents the supporting documentation related to this research effort.