Here is some information that will help.
1) Nixon did not want to give over the tapes for multiple reasons. Two of the most popular reasons he used were these tapes discussed issues of national security and he had the "executive privilege" of keeping them.
2) Nixon understands that there are several levels of government all with different functions. However, based on his actions, he believes that all government functions start and end with him.
3) Nixon's idea of executive privilege shows that he felt that the president has a certain set of protections/immunities that other citizens do not have. Nixon felt that his position as president gave him these powers.
4) Chief Justice Burger argues that the idea of executive privilege is determined by the Supreme Court, as they are the ones responsible for interpreting the law.
Without the primary source mentioned in the worksheet, this is the best information I can give you.