As @ andresrcs points out we cannot do your assignment for you but I think we can offer a bit of help.
Do these first commands work?
library(readxl)
assignment3_data <- read_excel("assignment3_data.xlsx")
View(assignment3_data)
cor(assignment3_data)
If so it means you have loaded the data successfully.
Next, what is
assignment3_data.pch16
I do not see why it would exist. You might want to start from there.