Here’s Michael J. Thomas of the American Civil War Museum giving a nice talk on the 57th Massachusetts, a veteran volunteer regiment in 1864 and 1865.
The video’s description reads, “The 57th Massachusetts Veteran Volunteers, one of four so-called ‘Veteran’ regiments was brand new to the front lines in May of 1864 when they marched off into the Wilderness. From then on, the regiment would see action in every single battle of the Overland Campaign. They would serve in the initial assaults on Petersburg, fight in the battle of the Crater, and after months in the trenches see their final action at Fort Stedman. White House guide Michael Thomas tells the story of a regiment that may have only seen one year of the war, but saw some of its hardest fighting.”