Update README.md

Author: thiagodnf

README.md

@@ -4,8 +4,16 @@ A comprehensive collection of Gnuplot examples
 
 ## Usage
 
+Install <a href="http://www.gnuplot.info">Gnuplot</a> on your machine and run by using Console the following script:
+
+```sh
+gnuplot script.gnu
+```
+
 ## Examples
 
+Click in the figures to go directly to the gnuplot script.
+
 ### Line Charts
 
 #### Basic Line