Scrolling is done with the Scroll toolbar buttons 
Click the button. The current visible window will slide to the left in the complete file.
Click the button. The current visible window will slide to the right in the complete file.
When you scroll left or right the positioning tool above the graph shows the relative position of the currently zoomed part (in white) with respect to the complete file.
Click the button and the cursor will change into a hand. You can now manually drag the current visible window within the complete file. Click the same button again to stop scrolling manually.