When first opening a chart it is zoomed out to display the entire chart. If you imported a PDF that already had progress annotated in it that will be drawn in color otherwise the entire chart will be white. The symbols of the chart will be shown when zoomed in closer. To zoom and move around the chart make sure the move mode is selected in the top toolbar.

Zoom

On a tablet: Use a two finger pinch gesture to zoom. Or double tap and drag.

On a desktop: Use ctrl and drag or double click and drag to zoom.

Move

On a tablet: Use one finger drag to move the chart.

On a desktop: Click and drag to move the chart.