Whom did Mowgli get the Red Flower from? What did he do to keep it alive?

He got the red-flower (fire) from the husbandman's son. He kept it alive by stoking the flames with dry branches.

“Is that all?” said Mowgli. “If a cub can do it, there is nothing to fear.” So he strode round the corner and met the boy, took the pot from his hand, and disappeared into the mist while the boy howled with fear.

“They are very like me,” said Mowgli, blowing into the pot as he had seen the woman do. “This thing will die if I do not give it things to eat”; and he dropped twigs and dried bark on the red stuff. Halfway up the hill he met Bagheera with the morning dew shining like moonstones on his coat.

“Akela has missed,” said the Panther. “They would have killed him last night, but they needed thee also. They were looking for thee on the hill.”

“I was among the plowed lands. I am ready. See!” Mowgli held up the fire-pot.

“Good! Now, I have seen men thrust a dry branch into that stuff, and presently the Red Flower blossomed at the end of it. Art thou not afraid?”

“No. Why should I fear? I remember now—if it is not a dream—how, before I was a Wolf, I lay beside the Red Flower, and it was warm and pleasant.”

All that day Mowgli sat in the cave tending his fire pot and dipping dry branches into it to see how they looked.