So the four scripts located to the specific repository (plotX.n) access the household_power_consumption.txt to produce the corresponding plots.
Note that the scripts and household_power_consumption.txt file have to be located under the same directory. Moreover lubridate r pagkage is required. Especially dplyr package is required for the plot1.R, however due to issues of subseting POSSIXlt objects further plotX versions do not use dyplr.
Dataset found at: https://d396qusza40orc.cloudfront.net/exdata%2Fdata%2Fhousehold_power_consumption.zip