Depending on the version you have, the data file is either in the Examples folder of the installation folder or in C:\Program Files\Adaptrade Software\Data. For recent versions, you can right-click on the chart and select "Select Price File" to select the file. If you don't have that, just delete the chart, go to the Build Symbols window, and select "Plot Symbol" to add the chart again.
You should save your data as csv. The user's guide explains in detail how to import data in the chapter Symbols and Settings, Symbol Library, Adding a Symbol.