How do i read this?

Hey guys, i was looking at the book modern chess openings, and they show the moves in a theory table. How do i read that?

One move at a time.
Not trying to be facetious. Just not understanding the question. The game fragments are arranged vertically and numbered. Read the moves from left to right. At the end of the line there is often a footnote reference. Those refer to continuations at the bottom of the page and sometimes for several pages.

it's kinda confusing but on the top of the page will be the name of the opening. underneath that from right to left will read the first standard moves of the opening. underneath that will be a bold face line. underneath the line will be columns of move orders read top to bottom. each column top to bottom is a different line based on whether white or black plays a different move at some point. through out the columns you will find small letters in parentheses. thesecond will be in alphabetical order and match up with footnotes underneath the columns that actually shows some what middlegame continuations from actual games.