Problem with arrow shape in flow chart in Latex

Question

I am making a flow chart for poster in latex. Here is my code. My problem is that i am not getting arrow heads but only straight lines. Here is my code where i introduced my flow chart

Here i introduced the shapes and arrow style. This is what i am getting

I need arrows between Rectangles. Could you please tell that where i am getting wrong?.

Answer 1

This can serve as a starting point ...

\documentclass[tikz, margin=3mm]{standalone}
\usetikzlibrary{arrows.meta,
                chains,
                positioning}

\begin{document}
    \begin{tikzpicture}[
node distance = 4mm,
  start chain = going below,
  box/.style = {fill=#1, draw,
                text width=32mm, align=center,
                font=\normalsize\linespread{0.8}\selectfont,
                on chain, join=by arr},
  arr/.style = {thick, -Stealth, thick}
                        ]
\node [box=red!30]      {xxx xxx xxx xxx};
\node [box=blue!30]     {xxx xxx};
\node [box=orange!30]   {xxx xxx xxx xxx xxx xxx xxx xxx};
\node [box=green!30]    {xxx xxx xxx xxx xxx xxxx};
\node [box=gray!30]     {xxx xxx xxx xxx xxx xxxx};
\node [box=yellow!30]   {xxx xxx xxx xxx xxx xxx xxx xxx};
\end{tikzpicture}
\end{document}

Since you not provide MWE (minimal working example: a small but complete document with your flowchart beginning with \documentclass... and ending with \end{document}, as you can see above) it is not clear how your flowchart should looks. So, for further help, please consider comments below your question.