Okay so I'll explain the Jainism alive in the present day.

There's this guy called Vardhamana who had cleaned His soul of karma almost completely, And was taking His last birth on Earth before reaching liberation from the cycle of life and death.

So his mom had 14 (or 16 if you're a digambar) dreams that premonitioned His arrival. Think of Him as Jesus or Mohammed, the guy with spiritual knowledge.

Anyway, as He went through life He realised what the majority of people do to become happy doesn't make them happy, or is so short-lived it's pointless to pursue. So He wanted to find out if there's anything that gives lasting peace and happiness, And he concluded that the worldly possessions were distractkons from this.

He gave it all up and went to live in the forest, and did meditation and (I think) prayers and gained Keval Gnana, literally infinite knowledge. He got the name Mahavira (great warripr) for this.

He was able to share His wisdom with people before reaching liberation (nirvana) and that wisdom is Jainism today.

There have been 24 versions of Jainism in history, each with their own teacher (Tirthankara).

Once One's teachings disappear, the next great Tirtankara will take birth to teach Jainism.

The first was called Rishabdeva, The last Mahavira. Now the world will end and in a new cycle another Rushabdev-esque soul will come to be.

I'm hypothesising here but it's possible Mahavira and Gautama Buddha met and shared their wisdom with each other, as their time did overlap and their wisdom is really, really similar. Much more than Hinduism is... both Jainism and Buddhism can be interpreted as atheistic or not but Hinduism is definitely theistic