How did Pocahontas help Lewis and Clark?

Answer 1

Pocahontas did not help Lewis and Clark, she was dead long before their expedition. You are thinking of Sacajawea:

Sacajawea (or Sacagawea) was born c. 1788. She was a Shoshone woman whom Toussaint Charbonneau, a French Canadian trapper, acquired from a Hidatsa warrior. Lewis and Clark would winter at the present site of Bismarck, North Dakota, where they met her. Sacagawea was 16 or 17 when she and her husband, Toussaint Charbonneau, joined the Lewis and Clark party in the winter of 1804-05. She became invaluable as a guide in the region of her birth, near the Three Forks of the Missouri, and as a interpreter between the expedition and her tribe when the expedition reached that area. She would give birth during the expedition to Jean-Baptiste Charbonneau on February 11, 1805, whom Clark later raised and educated. She also quieted the fears of other Native Americans, for no war party traveled with a woman and a small baby. She was with the Corps of Discovery until they arrived back in St. Louis on September 23, 1806. Some Native American oral traditions relate that rather than dying in 1812, Sacagawea left her husband Charbonneau, crossed the Great Plains and married into a Comanche tribe, then returned to the Shoshone in Wyoming where she died in 1884.