Here we describe the design and usability evaluation of a mixed reality prototype to simulate the role of a tank platoon leader, who is an individual who not only is a tank commander, but also directs a platoon of three other tanks with their own respective tank commanders. The domain of tank commander training has relied on physical simulators of the actual Abrams tank and encapsulates the whole crew. The TALK-ON system we describe here focuses on training communication skills of the leader in a simulated tank crew. We report results from a usability evaluation and discuss how they will inform our future work for collective tank training.