for above, it mentioned:
Root Mean Squre Error (RMSE) is the evaluation metric for this contest
does it mean RMSE of (test$Count-train$Count)? but its test$Date > train$Date
RMSE will calculate how close your predictions are to the actual values. This will take only test count into consideration. You can refer this course which provides a benchmark solution.
will look into that, thank you very much.