Exista-what?

I unfortunately am only 2/3 of my way through the article covering existentialism. I am once again on the verge of slight confusion. I feel as though the philosopher or author is very sophisticated and speaks in several different perspectives. He gives many different versions of the idea I think and speaks about all of them. I do not feel as though I kept up with the writing so far, except for minor exerpts. One piece that I may have understood was covering taking action. I believe it was along the lines of we must take action instead of letting others do if for us. We cannot be a victim of quietism, which is saying the other man will do what I cannot. I agree with this in that we should not take on this model. Whether or not I will comprehend to final third of his work is ambiguous, but I am hopeful; for some reason, I feel that it is compiling several of the topics we have discussed in class up to this point in the semester.