This is what I believe and understand is Hinduism:
Hope this answers some of your questions. This should be enough to give you a general perspective of Hinduism.
What are the basic tenets of Hinduism?:
There is no one Hinduism, and so it lacks any unified system of beliefs and ideas. Hinduism is a conglomerate of diverse beliefs and traditions, in which the prominent themes include:
Dharma (ethics and duties)
Samsara (rebirth)
Karma (right action)
Moksha (liberation from the cycle of Samsara)
It also believes in truth, honesty, non-violence, celibacy, cleanliness, contentment, prayers, austerity, perseverance, penance, and pious company.
What are the major Hindu deities?:
Hinduism believes that there is only one supreme Absolute called "Brahman". However, it does not advocate the worship of any one particular deity. The gods and goddesses of Hinduism amount to thousands or even millions, all representing the many aspects of Brahman. Therefore, this faith is characterized by the multiplicity of deities. The most fundamental of Hindu deities is the Trinity of Brahma, Vishnu and Shiva - creator, preserver and destroyer respectively. Hindus also worship spirits, trees, animals and even planets - which amounts to Nature worship!
What are the key Hindu scriptures?:
The basic scriptures of Hinduism, which is collectively referred to as "Shastras", are essentially a collection of spiritual laws discovered by different saints and sages at different points in its long history. The Two types of sacred writings comprise the Hindu scriptures: "Shruti" (heard) and "Smriti" (memorized). They were passed on from generation to generation orally for centuries before they were written down mostly in the Sanskrit language. The major and most popular Hindu texts include the Bhagavad Gita, the Upanishads, and the epics of Ramayana and Mahabharata.
How and when did Hinduism originate?:
Hinduism has its origins in such remote past that it cannot be traced to any one individual. Some scholars believe that Hinduism must have existed even in circa 10000 B.C. and that the earliest of the Hindu scriptures The Rig Veda was composed well before 6500 B.C. The word "Hinduism" is not to be found anywhere in the scriptures, and the term "Hindu" was introduced by foreigners who referred to people living across the River Indus or Sindhu, in the north of India, around which the Vedic religion is believed to have originated.
