The nVSD2e class is very weird, defining a lot of strange things, even having an own version of \document, but the culprit is that tocdepth is set to 0 since there is no explicit code like \setcounter{tocdepth}{3} as in article.cls so the default value of 0is applied, meaning that only chapters or parts enter the .toc or bookmarks, but the nVSD2e class does not even provide \chapter or \part macros.
There is no \tableofcontents or \listoffigures etc. command, no \contentsname defined.
The whole class looks like glued together without proper understanding of TeX/LaTeX.
In short: Setting tocdepth to a value higher than 0, i.e. 2 or 3 etc. settles this issue, depending on the desired ToC leveling. (See How to hide/show section levels in the table of contents? for more on this topic.)
\documentclass{nVSD2e}
\setcounter{tocdepth}{2}
\usepackage[bookmarksopen=true,bookmarks=true]{hyperref}
\usepackage{bookmark}
\title{How well does?}
\author{I.S.Hould Not Use This Class}
\begin{document}
\maketitle
\begin{abstract}
The effect is very easy to construct.
\end{abstract}
See \ref{intro}
\section{Introduction} \label{intro}
jack for none.
\section{Procedure}
here it is..
\end{document}

nVSD2edocument class available online somewhere? If so, where? – Mico Oct 22 '17 at 08:49mcodepackage available online? – Mico Oct 22 '17 at 08:57nVSD2e.cls, do you konw how I should\newcommandor something so that it woks for my case? – manjurul Oct 22 '17 at 08:57mcodelink: [https://www.dropbox.com/s/9o9ibt15013fipt/mcode.sty?dl=0] – manjurul Oct 22 '17 at 08:59nVSD2easdocumentclass, the bookmarking in PDF file works perfectly fine. But If I usearticleasdocumentclass, the bookmarking in PDF file does NOT work. – manjurul Oct 22 '17 at 09:12articledocument class is used but not if thenVSD2edocument class is used? (At least, that's the result on my system -- TeXlive2017...) – Mico Oct 22 '17 at 09:17nVSD2edocument class while I would, at the same time, like to get the bookmarking in PDF. – manjurul Oct 22 '17 at 09:23nVSD2eclass is very, very, very, very strange. Don't use it. – Oct 22 '17 at 15:05