There are three ways to do comments in Latex.
1. The standard way to do comments puts in % and then everything on the
line after it is commented out:
Say $y = x^2 + \beta$. %Here is a comment.
2. If you put \usepackage{verbatim} at the start of your file, you can
do multiline comments like this:
\begin{comment}
Here is the first line of the comment.
Here is the second line.
Here is the third.
\end{comment}
3.If you put \newcommand{\comments}[1]{} at the start of your file, you
can have the best way of all:
Say $y = x^2 + \beta$.\comments{Here is my comment. }
Note that if you use \usepackage{verbatim}, it creates an odd
command that makes everything after it in the file a comment. Suppose
you write:
\comment{Here is what I wanted to be my comment.} Here is some more
writing for my paper.
Then not only will the words in the brackets be a comment, but all the
words after the brackets and on the next lines and pages too.