This work investigates the design and usability of a novel eXtended Reality (XR) Vest, which combines two viewpoints for demonstration-based training (DBT). Traditional modalities for DBT, such as prerecorded videos and live instruction, are minimally engaging and potentially hazardous resulting in low motivation and knowledge retention. To combat this, works incorporate XR technology to improve training immersiveness, safety, and engagement. When worn by a trainer, our XR Vest enables trainees to have the first-person perspective of immersive XR environments on an integrated tablet while simultaneously watching the third-person motor movements. To test the XR Vest in DBT, 28 individuals completed three training sessions: 1) using an Oculus Quest 2 (baseline); 2) watching a DBT video on a desktop computer monitor (first-person perspective); and 3) viewing a DBT on the XR Vest (first-person and third-person perspectives). Following each session, the participants performed a memory aptitude test to evaluate their recall, a NASA Task Load Index questionnaire to investigate their perceived workload, and a System Usability Scale (SUS) questionnaire to measure the usability of the systems. A linear mixed-effect analysis showed significant differences between the temporal demand, physical demand, and frustration in the NASA-TLX scores and the integration and learnability features in the SUS scores. The results suggest that incorporating XR technology in first- and third-person perspectives within the XR Vest decreased workload and improved system usability. Future works should evaluate the benefits of this XR design in other domains where DBT is used.