People called the Adena lived along the Ohio river valley (in modern Ohio) during the Early Woodland period, beginning about 700 BC. These people probably chose leaders in a "big man" system. They got some of their food from hunting and gathering and fishing, and some of their food from planting squash and other plants (but they didn't have corn yet). They grew tobacco to use in religious ceremonies, too.
Adena people often built large mounds of earth. Some of these were burial mounds to put dead people in. When people died, their relatives would smear red ochre or graphite on their bodies and then bury them inside these big mounds. Sometimes they buried dozens of people in the same mound (not all at the same time! They buried the people one by one, when they died.). People buried carved soapstone pipes with the bodies for their souls to use in the next world.
Other mounds that the Adena people built were not for burials, like the Snake mound in the picture on this page. These mounds might have been to show what group or clan people belonged to in that area.