Firstly, you do not need to chart the data to read the spreadsheet. The signal comes when the last column has gone negative and then ticks up to less negative than it was. I usually make a comment alongside the signals - see May-June 2003 on the ASX All Ordinaries spreadsheet.
I have not provided instructions for creating a chart, because it will depend on what spreadsheet software and what version you have. I have Excel 2003 and to find instructions on how to insert a chart, go to Help/Microsoft Excel Help and in Search, type in Create a chart.
By the way, on the members' web site I publish a chart which is updated every month. That chart is not created in Excel, but in my Insight Trader charting software. The underlying calculations for the chart from Insight Trader are the same as for the spreadsheet, with one exceptio, thefinal number is not rounded to the neares ten. The spreadsheet was really only intended to teach the calculation. However, you can read the signals from it as explained above.