There are three major schools of Buddhism: Theravadin, Vajrayana, and Mahayana (we are Mahayana). There are some important distinctions between these schools. For starters, there is a time element to consider. The oldest form is Theravadin. These teachings came into existence around 200 BC and are based on what is known as the Pali Canon - a collection of old sutras that had not yet been written down. The Theravadin path is a religion of Perfect Masters and there all sorts of menstrual taboos. The people worship the priests who sit on throne-like chairs on the side of the temple. You will see them wearing yellow robes and find them believing in reincarnation.
There was a lot of trouble with this perfect master religion (see the Roman Catholic Church today) and as a result the Mahayana came into existence with a Celestial Savior (our Bodhisattva) around the time of Christ. With the Mahayana, here was no more worshipping of masters and priests. A bunch of new sutras came into existence too: the Diamond, the Heart, and the Prajna Paramita sutras, for example.
The Mahayana is close to Kashmiri Shaivism. Salvation is confined to this world . . . as is hell. We do not get close to our priests in any sexual way. We are supposed to be completely right-hand as are the Theravadins with the exception that they don't regard sex with men as violating any precept. Women don't count in the Theravadin path so male homosexuality is meant.
Zen (in China) became a further blending of Daoism and Indian Buddhism.
The Vajrayana is a blend of Buddhism and the primitive Bon religion of Tibet. It came into existence in the 7th century AD. The Vajrayana is both a Perfect Master and Celestial Savior religion except that they think our Bodhisattva has reincarnated in the person of the Dalai Lama. They have a very strong Left-hand orientation. Only the Yellow Hats are Right Hand.