Can any one please tell me how to set up testing server working with Laragon

this link should be important for you to understang how Laragon structure its files

https://laragon.org/docs/directory-structure.html

STEP 1:  Install local testing server and create a local MySQL database with phpMyAdmin or HeidiSQL.

http://webvaultwiki.com.au/Default.aspx

https://localwp.com/help-docs/advanced/how-to-use-heidisql-with-local/

STEP 1: Define local testing server in DW under Site > Manage Sites.   See screenshots below. 

New Server:

Testing Server Basic tab:

Testing Server Advanced tab:

Final screen:

Paste this code into a new php document and save as TEST.php. 

Right-click on document tab and select Open in Browser (localhost).

<?php
$con = mysqli_connect("localhost","your_username","your_password","database_name");

// Check connection
if (mysqli_connect_errno())
  {
  echo "Failed to connect to MySQL: " . mysqli_connect_error();
		}
		else echo "Successfully connected, happy coding!"
?> 

Hope that helps.

Dreamweaver doesn't support any database connection these days unless you are using php version 5.6 or less and have the old redundant server  behaviours installed.

what information did you indicate in the site setup concerning the testing server ?