If you're interested on a more visual/animated explanation for this and other gamedev topics, I highly recommend Yahtzee's Dev Diary series (starting with episode 1 and going forward chronologically): https://www.escapistmagazine.com/v2/category/yahtzees-dev-di... He sets out to make 12 games in 12 months, so he experiments with many different themes and mechanics, while showing what makes a game a game.