This device uses capacitive multi-touch technology which requires your skin to touch the screen. Screen calibration is not supported at this time.
If using a screen protector or wearing gloves, touch sensitivity may be increased by navigating: Apps icon > Settings > Display & gestures > tap (check) Glove mode.
If Settings is unavailable, tap the Dropdown menu (upper-left) then select Alphabetical. If still unavailable, refer to Manage App Icons.