Use the green Play Icon or red Stop Icon at the bottom of the screen.
The time bar is at the bottom of the Axiom Trend Graph. In the center of the time bar is an undo arrow, time interval, and either a green play button or a red stop button.
Clicking on the red or green button will toggle the graph in and out of live mode. You are in live mode when the red stop button is displaying. When the green play button is displaying, you are no longer in live mode.
Live data feeds from the right edge of the screen and progresses to the left.