Preeti,
Due to security precautions, we are not able to open any .rar files. If you want to share a code with us, please use jsFiddle.
To reduce your chart's width, you can do it via CSS (on the chart's container div) or using
chart.width property (like in the example you shared above).
https://api.highcharts.com/highcharts/chart.width
Kind regards
edit: here you have a working demo:
https://jsfiddle.net/gh/get/library/pur ... ock-chart/