Rubuta ci gaba don wannan sakin layi - Mann ya yi aiki tare da Rundunar Sojoji ta 17 a cikin Yakin Spain-Amurka, yana shiga cikin yakin El Caney
da kuma Siege na Santiago. Ya sami lambar yabo ta Silver Star don aikin jaruntaka a El Caney. Mann kuma ya yi aiki a cikin Philippines a 1899 da farkon 1900s. Ya kammala karatunsa daga Kwalejin War Army a 1905.