QUESTION/PROMPT Although Existentialism itself isn’t a moral system or theory an

QUESTION/PROMPT
Although Existentialism itself isn’t a moral system or theory and generally avoids strong moral claims, consider what role Sartre’s claim that existence precedes essence might mean for morality and human choice. He says of the phrase, “We mean that man first of all exists, encounters himself, surges up in the world – and defines himself afterward.” (p. 3)
If our choices are all we are (apart from mere existence), then what impact do my choices have on any moral claims I, you, or others make? Am I really responsible for all of mankind in the act of choosing this or that course of action?
INSTRUCTIONS
Word document (doc,docx) only.
Double-spaced, 1” margin on all sides.
Times New Roman or Calibri font set at 12 only.
No large spaces anywhere.
There is no page length requirement. However, short answers are probably not going to be enough. There is a lot of information to discuss, and this is a college-level course. I expect serious effort.
Cite appropriately. You may use outside sources.
NOTE:
Quality counts. Grades will reflect the extent to which I see thoughtful answers that reflect your engagement with and understanding of the material. However, it is also important follow the formatting and response instructions and that you actually answer the prompts. I will take off points for not following these instructions. 
Sources:

https://philosophynow.org/issues/15/A_students_guide_to_Jean-Paul_Sartres_Existentialism_and_Humanism