There are no special instructions when it comes to using the glass nail file, but here are some general uses:

- You should file in one direction from the side of the nail to the tip.
- It’s possible to file in both directions, but generally speaking, it’s good to file in one direction to give you better control and less friction when shaping the nails. 
- You can use the tip of the file to clean dirt and debris from under the nail as well.