To build a Tesla coil that operates on 12 volts DC and 9.9 amps, a high-frequency transistor oscillator is essential. Recommended resources include books from teslapress.com and lindsaybks.com, which provide detailed instructions on constructing Tesla coils. A Tesla coil consists of a primary winding with a few turns of wire and a secondary winding with many fine wire turns, designed to resonate with the arc frequency. Proper adjustment of the coil's components is crucial to ensure safe operation and prevent shocks. For comprehensive guidance, acquiring a specialized book on Tesla coils is advised.