The indicator uses FXCM Report API in order to load the history of trading and then display it on the chart. Just install the indicator and apply it.
The indicator displays historical trades. If you move the cursor over an arrow and wait a bit, the tooltip with details about the trades are shown:
By default, trade markers are shown above/below a bar. You can change markers position from "at bar" to "at price" in the indicator properties. Unfortunately there is an issue with the at "price" mode: currently the markers are displayed between bars instead of be shown at the center of the bar. This problem will be fixed in the next update of the Trading Station.
Please note that the indicator does not update automatically when the a bar appears, or a new trade is closed. This is made intentionally to avoid exceeding load on the report server. So to update the information just right click on the indicator legend (the text at the top left corner of the chart) and choose "Refresh" command.