What do doctors and medical staff actually do to keep COVID patients alive?

While most of us who follow the news know about the importance of ventilators when the situation is dire, is there an established protocol for treatment upon entry into the hospital and possibly the ICU? Has this changed or evolved over the past 3 months? I wonder if there are now actions that some doctors have found that “work” in improving the probability of a positive outcome. And because medical staff around the entire world are dealing with similar symptoms, is there even a way to communicate findings to everyone else? Are the WHO or some other organization supposed to be able to aggregate and communicate new information?

Here is a Chinese handbook on Covid-19 treatment: