This is actually the shiva beej mantra. Listed here the “HA” stands for shiv and “UM” means Sadashiv. To evoke the blessings of Lord Shiva, chant this mantra maintaining lord shiva in mind and focusing on him only. Following that, commence chanting the mantra while meditating on Bhairav Baba. https://www.youtube.com/watch?v=0vLISs2kzMI