Line Charts are the standard way of looking at the historical value of an analogue channel in a dashboard panel.
It provides a simple line graph showing the value of the channel (or channels, as this type of panel can show several channels at once) over time.
Hover your mouse over a line to see details of the channel at that point in time.
Left-click on an individual line to open the navigation menu for that channel.
This allows you to follow that channel to the asset it belongs to, trend it over time, compare it to other points of data, or view other values like it across your system.
Right-click on the line to open the editing menu for that channel. This will allow you to change the type of the chart, as well as moving the channel to a different panels.
Hover your mouse over the background to see the value of each of your channels at that point in time.
Left-click and drag to highlight a period of time. When you release the mouse button, you'll zoom in on that time-frame.
Right-click top open the menu and alter the scaling. By default, your line chart will be scaled to the minimum and maximum values of your channel. In some cases, this ends up being far too zoomed-out for you to see detail. To resolve this, right-click on the background of the chart, choose Scale and change it from Full Range to Auto.
Left-clicking on the background opens up a few options for analytic reports and navigation.