Find the reference mark, or the top of the story pole; both of which should be clearly marked. This will tell you where to line up the pole when used for installing siding. It will also tell you where the measurements start from.
Look for evenly spaced marks. If these marks are not labeled, they probably indicate the spacing between each course of siding. They will be adjusted so you will have a full reveal of siding along the top and bottom of window trim. If they are not for siding they will probably indicate the location of studs or joists.
Other marks on a story pole will be labeled to tell you what they are for. These marks could be for locations of windows or doors or where to drill holes.