Summarize this article:

Use the moisture that remains in your right hand. Wipe from the upper part of the head downwards (from the back of the head towards the face). It is recommended to wipe the length of at least one finger. Wiping can be done with one finger only; however it is recommended to use three fingers together (the middle finger, index finger and ring finger). The moisture must reach the scalp. However, if the hair is so short that it can not be combed, it is sufficient to wipe your hair. While wiping the head, your hand should not touch your forehead. Doing otherwise will cause the water of the forehead to mix with the wetness of your hands.

Summary:
Wipe the front most quarter of the head.