High Plains Community Schools is set to open its doors for the first day of classes Aug. 14 across both the Clarks and Polk sites with an early 1:30 p.m. dismissal that day.HPC’s back-to-school night is Aug. 12 starting at 5:30 p.m. in Clarks for the elementary building and 7 p.m. in Polk for junior high and high school.Two of the major changes in the student handbook deal with a new total cell ph…