1) Slide outward the top cap marked with the dot symbol until the filling hole is revealed;

2) Add your preferred e-liquid through the filling hole;

3) Slide the top cap back into place.

CRC version:
1)Simply pull the drip tip without removing it;
2) Slide outward the top cap marked with the dot symbol until the filling hole is revealed;
3) Add your preferred e-liquid through the filling hole;
4) Slide the top cap back into place and press drip tip into place.