I don't know about graded written paper with rubric as an international student plz guide me and show me some sample

If your teacher for which you wrote this paper didn't use a rubric for grading it, then you do not have to submit a grading rubric to Princeton.

Just attach the paper in the format they request which is I believe a. PDF file.

If you don't know what a rubric is, it is a grading matrix. Typically on the Y-axis are the Criteria and on the X-axis are the definitions of the grading metric.

So there might be something like Introduction, Thesis, Conclusion, Grammar, Spelling, Flow. etc down the Y-axis and the different point values for how well you perform that task on the X-axis. Then the teacher adds up the points. So if you might get 36/40 possible points on a rubric which is 90%.

Does that make sense now?

Hope that helps.