Most Pantos will suggest placing your needle in the highest point before scrolling your fabric up. That way you know you won't chop off the top edge of the design.
If you don't want the design to run off the edge, you'll have to do some planing first.
Adjust where the design starts so that the end falls within the area you want quilted. Then you freehand in the small areas before the first design and after the last one to make it pleasing to the eye. (you can sketch it onto the panto)
And definitely check out the youTube videos.