There is no creed here, and no council ever met to fix one. What holds the traditions together is a set of shared terms, used differently by different schools but recognisable across all of them.
Dharma is the most important and the hardest to translate: the order of things and one's obligation within it, which varies by role, stage of life and circumstance rather than applying uniformly. Karma is action together with its consequence, working across lifetimes. Samsara is the resulting round of birth, death and rebirth, and moksha is release from it, the highest goal, though not the only one the traditions recognise, since duty, prosperity and pleasure are also counted as legitimate human ends.
Behind these lies the question of what the self ultimately is. The Upanishads pose it as the relation between atman, the innermost self, and Brahman, the reality underlying everything. Advaita Vedanta answers that they are not two; Vishishtadvaita holds the self to be real and distinct but wholly dependent on God; Dvaita holds God and the soul permanently separate. These are not sects so much as rival readings of the same texts.
Scripture is layered. Shruti, that which was heard, means the Vedas and the Upanishads and carries the highest authority in principle. Smriti, that which is remembered, includes the Mahabharata with the Bhagavad Gita, the Ramayana, the Puranas and the law books, and in practice these are far more widely read and recited.
Practice ranges from temple worship and household ritual to pilgrimage, festival, recitation, yoga and ascetic withdrawal. Puja, the offering made to an image understood as hosting the deity's presence, is the most common form; what the image is taken to be varies considerably from one tradition to another.