I recomend you use file.choose() function.
file.choose()
This open other window, you must find the file and click in open. Next, in the console appear the direction of this file in " ". Copy this.
And paste in the read.csv()
dt<-read.csv("C:\\Users\\Downloads\\customer_data.csv") # Remember copy all " "
Righ now, your data name is dt
For view the data
View(dt)
head(dt)
summary(dt)