Where exactly is the editorial section of the newspaper, and is Us Weekly an opinion mag?

Answer 1

It varies, often depending on the size of the paper. Larger papers place it in the second or "B" section, along with letters to the editor and op-eds (shorthand for "opposite of the editorial" in sense of its placement, not opinion).

Us Weekly is not an opinion magazine; it's a high-end glossy tabloid. Opinion magazines are publications such as Atlantic Monthly, Harper's and the National Review.

Answer 2

Usually in Section A - the main section with the front page

one or two pages from the end of that section

or you could look in the index at the bottom of the front page for Editorials