You will need charts (maps). You can use a scanner and scan your own maps. The ChartPlotter program will need some information about which area is covered by the chart. This information is produced using the CalibrateChart pogram.
A referece point is a point (x,y) on the image with a known latitude and longitude.
A reference point is created by FIRST marking it on the image with a mouse click (a cross will apear on the image).
Then choose "add ref" in the menu.
A dialog window will pop up. Enter the latitude and longitude for the reference point.
Latitude is given in this format: 12S34.56 or 12N34.56
Longitude is given in this format: 12E34.56 or 12W34.56