[Tex/LaTex] drawing a basic line segment

Question

please excuse my ignorance because I am VERY new to latex (2 days).

Before I ask my basic question, is anyone aware of a beginners guide to creating basic docs in Latex? I have seen a few "cheat sheets" out there but nothing that provides the basics of getting started.

Anyways, here is my question.

I am looking to create a simple line segment, (180 degrees) with arrows on both ends. On this line segment, I would like to plot and label three points, A, B, C.

Answer 1

Like this?

\documentclass{article}
\usepackage{tikz}
%\usetikzlibrary{positioning}

\tikzset{
  mynode/.style={fill,circle,inner sep=2pt,outer sep=0pt}
}

\begin{document}
  \begin{tikzpicture}
    \draw[olive,thick,latex-latex] (0,0) -- (7,0)
    node[pos=0.25,mynode,fill=red,label=above:\textcolor{red}{A}]{}
    node[pos=0.5,mynode,fill=blue,text=blue,label=above:\textcolor{blue}{B}]{}
    node[pos=0.75,mynode,fill=green,text=green,label=above:\textcolor{green}{C}]{};
  \end{tikzpicture}
\end{document}