Could someone please give me some information on what Tantra is? Is it rituals? How does it help one reach nirvana?
Therevada and Mahayana are paths of renunciation. However Buddhist tantra asserts that the Buddhas gave other teachings based essentially on the purity of the mind and it's latent qualities. One meaning of tantra is continua or continuation and this can be see as referring to the mind itself or the teachings. So the basic principle of tantra is the pure view of everything - viewing everything all the time like a high Bodhisattva or a Buddha would view things. This view transforms our relationships with the outer sense objects and with ourselves and others. How can we do this? Afterall I can run around all day dreaming that I'm the President of the United States or something? We can do this because our mind is a sleeping Buddha. All sentient beings have the essence or at least the seed of Buddhahood (this is treated differently by different lineages in Buddhist tantra).
Rituals in tantra are methods to accumulate merit and wisdom. That's all they are although rituals are also blessed. Tantra is also a path of charismatic Buddhism or a path of utilizing blessing in order to attain Buddhahood. The rituals or methods are one means to awaken the sleeping Buddha in us.
All the methods of Buddhist tantra eventually point one to Buddhahood (I have to say eventually because there are levels of the methods and some are more direct than others).
_________________Kirt's Tibetan Translation Notes
"Only you can make your mind beautiful."
HH Chetsang Rinpoche