In this post, I will explain how to use the package : numencl in Latex.

1. You can find the package and its documentation here, if it is not already in your latex distribution:
2. Add the following commands in your preamble:
   \usepackage{nomencl}
   \makenomenclature
   \renewcommand{\nomname}{List of Symbols}
3. In your document, whenever you introduce a new symbol or variable, add the following command to introduce the new symbol (e.g. X)
   \nomenclature[]{$X$}{Explain here what does X mean}
4. Use the following command wherever you need the list of symbols to appear in your document:
   \printnomenclature
5. Download the makeindex executable file from CTAN website here into your document directory.
6. Go to the command prompt in your directory and run the following command:
   makeindex hfilenamei.nlo -s nomencl.ist -o hfilenamei.nls
7. Compile your file!