They will not react the way you'd like. They'd be absolutely terrified, won't understand at all, and will try to kill you. They won't be able to comprehend the advancements we've made in technology. Shit, my grandma doesn't understand some of the new technology we have, and she's more civilized than they ever will be.

Many people have speculated what would happen. Some even tried, which, surprise, ended in some of the tribes death. And then the rest of the tribe didn't even care about the gifts, because they can't comprehend that. All they can comprehend is you killed one of their own and anything else involving you bad and you need to go away. https://en.m.wikipedia.org/wiki/Sentinelese

In 1880, in an effort to establish contact with the Sentinelese, British naval officer Maurice Vidal Portman, who was serving as a colonialadministrator to the Andaman and Nicobar Islands, led a group of Europeans to North Sentinel Island. Upon the arrival of the armed group, the islanders fled into the treeline. After several days ashore, during which they found abandoned villages and paths, Portman's men captured six individuals, an elderly man and woman and four children.[28]

The man and woman died shortly after or before their arrival in Port Blair, likely from disease, and so Portman attempted to befriend the surviving children by giving them gifts before returning them to North Sentinel Island, in hopes that the children would help village elders realise the British were friendly. The attempt was unsuccessful, likely due to the aggressiveness of Portman's visit and the fact that his efforts resulted in the deaths of two Sentinelese people.[12][29] Additionally, due to differences in culture, the children might not have recognised the gifts as such.