I have always found Hinduism complicated! Every time I ask a Hindu he thinks I am mocking him and refuses to answer ANYTHING related!
Since I follow monotheism I do not understand the concept of having soo many gods who can fight, reproduce and kill each other...How can a gods reproduce or die?
For Greek mythology I liked it because it was no one's religion in today's world so I took it as a story book! But if I did that to Hinduism it would be sort of insulting the religion...
Here it will be easier to understand if Hinduism is seen as a religion that went through phases.
First, it was the religion of steppe wanderers, who worshipped nature, and put names to natural phenomena - the thunder and lightning, sunshine, moonlight, the dawn, fire, the wind, water; these were Indra, Surya, Chandra, Ushas, Agni, Vayu, Varuna. This was the religion celebrated in the exuberant verses of the Vedas. The Vedas, btw, were divided according to purpose; if you are not planning a formal, academic programme of study, only the Rig Veda need interest you.
Next, for reasons nobody has managed to explain, it sat down and became a collection of philosophical explorations and speculation about cosmogony. This phase, marked by the books of the Brahmanas, Aranyakas and the Upanishads, dealt with cosmic order. It describes the universe being born, or created through a cosmic sacrifice, and how, to keep it going, a series of rituals and sacrifices have to be performed.
On the one hand, very fine minds explored the meaning of the universe, but it was on the other hand a recommendation to thie oîrdinary citizen to help to keep the universe in good order. That part of it and the greed of the priests made it a tense time, just ripe for a religious revolution.
This second phase was also the phase when old poems and folk tales were put together to form two epics, the Ramayana and the Mahabharata, the latter huge compared to the former.
The story of the first is simple, how a king kills a boy accidentally, how he is cursed by the boy's father, how he loses his son to the curse and dies of grief, and the son's adventures in exile, in the forest, along with his wife, who refused to leave him, or his loyal half-brother. In the forest, the wife was abducted by a demon king, who swept her away to his distant kingdom. The rest of the story is about how the young prince gathered allies, raised a strange army and attacked and defeated the demon king, before returning home to his own kingdom. It has very dark patches, and also very moral homilies about the nature of man, the duties of a king, faith and loyalty, treachery and courage - in fact, almost every human emotion has its role. I hate reading it because the prince I was named after is murdered while he was praying, unarmed.
The story of the second is again simple, but the story itself starts telling other stories! A royal family is plagued by accidents and by strokes of misfortune through several generations. The story opens with two sets of cousins playing together, training together and finally, fighting together. Clearly, this could not last, so, during a game of dice, one set of cousins, the sons of the king then on the throne, teased and provoked the others to higher and higher stakes, till they had lost everything and had to go into exile. On their return, they asked for their kingdom back, were refused and fought for their rights in a titanic battle that lasted for seventeen days.
This was the phase, perhaps roughly between 1000 BC and 500 BC, where, on the one hand, the philosophers took their thinking to very high, lofty levels, and thought of the nature of the universe, and of creation in ways that still impinge on the thoughts of contemporary society; on the other hand, the Gods were participants in the affairs of men, and were in and out of these epics, just as they were in The Iliad and The Odyssey.
In the third phase, which came after the long period of Buddhism and Jainism, it was a philosophical counter-attack by the brilliant thinker, Sankaracharya, a deep thinker and theoretician about the singular unity of God and creation, of Advaita, that put a focus to the efforts of Hindu revivalists throughout India, and gradually weakened Buddhism. From this ninth century onwards, Buddhism lingered on with less and less influence on society, until the attacks by the Turks killed off most of the monks and saw the destruction of their monasteries and what we call their universities. They still lingered until the 14th century. It was a religion which had millions following it, and did not vanish overnight.
It was at this time, late in the day, that temples appeared, and idols began to be worshipped, ironically, just before their biggest enemies appeared on the scene. It was here, with the amalgamation of northern and southern practices, that the contemporary Hindu pantheon was more or less established, that place was found, with a little juggling, for the Buddha to become another avatar of Vishnu, and the trinity of Brahma, Vishnu and Siva, creator, preserver and destroyer, took hold of popular imagination. Indra and the old nature gods of the steppes were far less prominent and petered out. They had not come out of their pages in the epics with a great deal of credit and it was difficult to bend in worship to a god who did not behave with great dignity or godlike aloofness.
It was also at this stage that the Bhakti movement started and took hold. This was a movement by reformers who questioned the slide back to ritual that the Hindu revival brought in its wake, and presented a far more personal view of God, a God who cared, and who rewarded the love of his (or her) disciples with love. Here God was represented by princes and players from the epics and by goddesses from the Buddhist practice of Tantra, which elevated goddesses from their earlier subsidiary roles to eminence. Much of this went on developing and growing right to the sixteenth, perhaps, in some senses, even the seventeenth century. It culminated very strangely but brightly, with the Sikh religion.
As for the period between the fourteenth to sixteenth century and today, it was a period when Hinduism went through much of what other religions have experienced, a reversion to fundamentalism, but fortunately for everybody, a fundamentalism without real teeth. In the absence of good thinkers and philosophers among the fundamentalists, they have not been able to represent any stark and austere version of the relaxed religion that they thought Hinduism had become, and so failed to really bring out the lunatic in people.
These are the four broad phases into which you might see the growth and development of Hinduism. This may help you understand why the Rg Veda sings of Indra, but there are no temples to him to be seen. But what you probably want is a made-easy, a Guide to Hinduism without Tears. I could do worse than refer you to the Amar Chitral Katha comics, which are more or less accurate, convey the prejudices and foibles more or less intact, and comes in bite sizes.
Please ask for clarifications as I don't know how much depth would be appropriate.