Here's a list of each of the user roles and an explanation. I don't recommend making anybody but yourself an admin. I usually put other authors in as an author or a contributor depending on how well I know them.

The roles in descending order of power:

Admin - Any user you add as Admin will have all the same powers as you. Don't set anybody as an Admin unless you really trust that person.

Editor - An editor can create articles and edit other's articles without permission from an Admin.

Author - An author can create articles without permission from an Admin.

Contributor - A contributor can create drafts of articles. They can not publish an article themselves. An Editor or Admin must publish their articles for them.

Subscriber - There is almost no reason to need this role. A subscriber can view the backend, but cannot do anything within it. A subscriber is like a spectator of the backend operations.