Final answer:
Primary sources such as diary entries and personal accounts provide firsthand insights into soldiers' experiences during the Civil War.
Step-by-step explanation:
To learn about soldiers' firsthand experiences during the Civil War, historians rely on primary sources such as diary entries, letters, and personal accounts. These sources provide direct and immediate insights into the thoughts, emotions, and experiences of soldiers on the front lines. For example, diary entries like Jacob Stroyer's account of his experience in the war offer a firsthand perspective on the lives of soldiers. Another important source of information are the newspaper accounts of the time, which reported on battles, casualties, and other developments. While presidential reports and telegraph messages played a role in relaying information during the war, they are not considered firsthand accounts of soldiers' experiences.