As your test runs, Flood will plot the results it receives into a real-time display. Your flood will need to last at least one minute and return a few data points before the graph is displayed.
You can hover your cursor over any point in the graph to see the metrics at that point.
The blue line is the response time, and it is a measure in milliseconds of how long it took to get a response for each step or transaction of your test.
The orange line is the number of virtual users that are currently running through your test steps.
The green line is the transaction rate, and it is expressed in requests per minute.
The metrics in the graph are for all transactions in the flood that have been executed so far.
Below the graph, you'll see the steps that you specified along with some metrics for each step (as opposed to the total metrics that are graphed). You can also click on the arrow on the far right to get more information about the transaction.