Not knowing how WWI started is probably one of the lesser pieces of misinformation. The bigger ones would be thinking that WWI was just the Western Front and that the Western Front was only static trench warfare. Those feed into the perception that nothing significant happened during the war therefore there's nothing worth studying in it. The reality is that not only was WWI extremely historically significant but that every major modern military weapon (with the exception of the nuclear bomb and missile) was either pioneered or brought to the forefront during it.
Aircraft, automobiles, tanks, machine guns, artillery, modern tactics, chemical warfare.
You're right. WWI was their first large-scale use, and no one knew what to do with them.