To install Web application on your website from Plesk control panel please follow the following steps:-
1) Login to Plesk control Panel.
2) Click on "Domains".
3) Select the "domain" on which you want to install the application.
4) Click on "Web Applications".
5) Click on "Install Web Application".
6) Enter the "Application Name" you want to install and enter the "Search option".
7) Click on "Install" button from the list to avaliable application version.
8) Click on "I AGREE" check box and then click on "Next".
9) Enter the required details in the feilds and press Install.
10) You can now access your web application to your web URL. If you have installed
application in the sub folder in your directory then you can access web application
from the URL "http://your-domain-name.com/subfoldename".
