The accompanying photos will help readers understand what a ger is and how it's set up. The short answer to the difference between a yurt and a ger is that "yurt" is the Russian word for the circular tent-like dwelling that Mongolians call a "ger ["gair"], which also means "home."  For a discussion of the difference between a ger and a yurt, see https://www.panoramicjourneys.com/Know/Interesting-Facts-about-Mongolian-Gers. For a history of the yurt/ger, see this National Geographic discussion: http://nationalgeographic.org/encyclopedia/yurt/.