The MerKaBa is the electromagnetic field around all living beings, created and sustained by consciousness.
The Ancient Secret of the Flower Of Life- Vol 1 and 2, By Drunvalo Melchizedek begins the practice of the tetrahedral Living MerKaBa meditation found in Vol. 2.
Here is a great audio by Drunvalo Melchizedek to assist in the MerKaBa meditation. He used to say it took daily practice for 2 years for the MerKaBa to be stable, yet things have sped up a lot since then. Daily practice is required- as well as emotional release as suppression comes to the awareness. You may find emotional transmutation methods here on my site, or in Wholistic Health Made Easy. Drunvalo made this audio a long time ago, and it helped me as a daily guide in the first few months of the process. At a certain point you make it your own meditation with out auditory guidance.
Balancing the electromagnetic field around the human body is a process of emotional and mental evolution experienced individually through practice. This process may not be rushed, and is an inner process of application.