The tool opens to show a ‘one-quadrant’ graph, covering points (0,0) to (10,10). Select the ‘four quadrant’ button bottom left to switch between this and a graph covering (-10,-10) to (10,10).
On the left there is a set of tools - the ‘add line’ tool is selected by default. With this selected, you can make lines by clicking on the chart to indicate the start and end points of the line. The co-ordinates you enter then appear in the data table. There is a colour picker next to the ‘add line’ tool - you can use this to change the colour of the line.
Click on the top-most tool (the ‘add point’ tool) to add isolated points (these will not be part of a line). Or, click on the bottom tool for an eraser with which to delete individual points or lines.
To delete all points on the graph, click the ‘Clear all data’ button under the data table.
Use the buttons under the data table to hide or show the chart, the data table, or both.
Clicking ‘Set up’ opens a menu in which you can choose background maps - e.g. a treasure map.
Clicking ‘Reset’ undoes all changes, returning the tool to its default state.