First, go to a setlist. If the setlist contains at least one song with an attached chart, then open the chart (chart icon at the far right of the song).
The chart viewer has different behavior on 1st generation iPads. You must use the forward/backward arrows to advance the charts. The window title will show the current song's order in the setlist and the title.
On 2nd generation iPads and newer, you can also SWIPE left/right to advance the charts in setlist order.
Again, if a setlist has at least one song with a chart attached, this will work. If a chart is missing, you will see a blank chart that says "No Chart Available"