Start with some definitions: anthropology covers a great many fields, but a general definition could be that anthropology "deals with all that is characteristic of the human experience." Ethics, as in ethical issues, deals with "rules of conduct recognized in respect to a particular class of human actions or a particular group."
Keeping these definitions in mind, anthropologists should approach research with people as keen observers, noting and recording actions, interactions, and outcomes following such encounters objectively and interpreting the meaning of such observations without personal biases or beliefs.
Anthropologists should not interfere with the people or experiences they are observing. They should not create situations in which the subjects are likely or forced to act in ways that would be different from what would be chosen if they were not being observed. Anthropologists should not influence thoughts or actions by anything they do or say; their goal is to observe the subjects and learn about the ways in which the subjects live through those direct lessons without any external impact that might change the subjects or the way in which they are living, thinking, and acting.