Q:

How can I customize/design the View Article page

I want to customize and design the view page for articles   I also want to add related articles module and move next and previous articles on the article page. 
How can I do that?  
Please advise...

A:

If you would like to change the structure/styling for an Article view, you need to create a Template Override, all of which is explained here:
http://docs.joomla.org/How_to_override_the_output_from_the_Joomla!_core
Template overrides allow us to edit the view of an extension without editing the core file which may get overridden in an update. 
So once you have you override done, you can now edit:

ROOT/templates/YOUR_TEMPLATE/html/com_content/article/default.php  

Hope this helps

