Let's get started.
Fire up the Operations Manager Console to the Monitoring section, then open the Windows Computers view (or any section where you access the computer health view, such as SQL)
Find a server you're interested in or simply select one from the list.
When selected, a graph should display such as the following:
Open up notepad and past the contents, which should look similar to the following:
Save the file with an xml extension
Select the XML file created earlier; accept the import defaults when prompted
This should populate the Excel spreadsheet with an X and Y column. The first column is the date/time stamp and the Y column is the performance data.
This should yield a graph in Excel such as the following:
Right-click on the graph line and select Add Trendline
Generally, accepting the default will paint a trendline that is helpful for finding issues such as a memory leak or consistent data usage on a hard drive. However, you can play around with the trend to perform longer-term forecasts. I added 50 periods to the end of my trend line to see how memory might look in the future after my data set.