1. Download the zip file https://d396qusza40orc.cloudfront.net/getdata%2Fprojectfiles%2FUCI%20HAR%20Dataset.zip
2. Extratct into a folder called "UCI HAR Dataset", this folder should be at the same level as the folder containing the R scripts
3. Run 'run_analysis.R'

A full description is available at the site where the data was obtained:

http://archive.ics.uci.edu/ml/datasets/Human+Activity+Recognition+Using+Smartphones