The image below shows the buttons & ports of the Apple Pencil.
Turns on the Pen, Doubletap the top of the pen a blue light will be displayed (see 3).
This port is the charging USB-C Port
Note: You’ll need to be gentle when connecting the charger to avoid damage to the charging port.
Displays the status of the Pen, Red = charging, Blue = On Green = Charged
Note: DON’T apply firm pressure to the screen this will ensure the screen keeps working properly and the pen tip won't get damaged.