Idon’t understand when it says first across the y-axis and then across the x-axis.?

Think about what "reflection" means in this situation.  You have a point (-2,9) which happens to be in Quadrant II.  You are to reflect this point about the y-axis.  The y-coordinate, 9, stays the same, but the x-coordinate changes to +2.  Note that +2 is the same distance from the y-axis as was the original -2.