Lie

     The ball is not sitting on a pool table.  Not all that many flat surfaces are encountered, except off the tee, of course.  The slope of the lie of the ball has an effect on the direction and the distance of the shot.  Which, oddly enough is why there is a lie meter on the main screen.  It looks like this.

     The effect can be determined by the arrows below and to the right of the golfclub.  The arrow below shows how much the shot will be pushed to the side by the lie.  The shortest arrow is 5 feet and about the most you will see is 25 feet.  In the example above, the lie will make the ball go about 15 feet to the left, therefore, the aim point must be adjusted to the right in order to compensate.  This is for full shots only, chips are not affected as much by the lie and lesser compensation is required.
     The right arrow shows that the ball will go further than expected.  In this case, reduce your shot by 5 feet.  Either through adding loft or changing to another club.  If this arrow had pointed up, distance would have been added.  Even with reducing distance, down arrows out of the rough can be chancy.   If you are trying to hit over a hazard, it may end up there.  Off the fairway, the compensation is more accurate.
     Elevation is another area where your total shot distance must be adjusted.  In the example, the ball is 33 feet above the hole at a distance of 123 yards.  First convert the feet to yards which gives you 11 yards.  Since it is above, you subtract the yards to give a total shot distance of 112 yards.  This could make the difference between a 7 foot putt and a 30 foot putt.  Personally, I'd prefer to putt from seven feet. 
     In the bottom left corner of the meter indicates that the ball is in the rough, but, you knew that.  Somewhat redundant, this portion of the meter.
     And the only thing left is the wind.  This can be hard to adjust for.  Different clubs are affected more or less.  Generally, the higher a shot goes in the air, the more the effect of the wind.  A headwind directly on will push the ball back around 10 yards, so that much must be added to the distance.  Just as a tailwind will add around the same.  If the wind is quartering use 5 yards.   Which is the case in the example.  In breezy condition, a full side wind will force the ball about 30 feet to the side indicated by the arrow, and the aimpoint must be adjusted to the opposite side.  Once again, chips are not affected as much by the wind.
     So, there are four things contained in the lie meter which may affect the shot.  They are all put together and then a final result is achieved which is your aim point.  Try to hit 100% shots so bad snaps don't have as much of an affect on the shot.