These are the following steps for Ajna Chakra Meditation,

• Sit in Sidhhansan. Hands on knees, eyes closed.
• Perform simple Vivekananda pranayama, or Anulom Vilom. for 10-15 counts and attain Kumbhak. Keep breathing again and get into Kumbhak again – repeat.
• While in kumbhak bring your attention in between your eyes. Imagine a glowing energy here and focus on it.
• Do not move, be still, focus just on Ajna Chakra i.e. energy in between eyes nothing else.
• If you find difficulty attaining here, make a plus sign with your nail in between eyes and focus on that sensation.

In Hath Yoga, this is called Shambhavi Mudra.