Joomla assign positions to module i.e., position tells where you want to place th module in the page. You can assign the position by following steps:

• Login to backend of your website(Joomla administrator).
• Go to Extensions --> Module Manager (You will get a page displaying all the modules)
• Search for the module which you want to display on the front-end. Click on the name of the moduleand you will find the edit form of the module. Assign position to that module where you want to display the module on the web pages.
• Now Go to the Menu assignment tab.
• Here you will get a drop down for module assignment having 4 values given below:
  • On all pages --> Display the module on all web pages.
  • No pages --> Does not display the module
  • Only on the pages selected --> Display only on the web pages selected in the menus selection field.
  • On all pages except those selected --> Display only on the web pages not selected in the menus selection field.
• Choose any 1 option from the above according to your requirement.
• Now you can check the menus in which you want to display the module and save the information. Now it will display the module according to the settings you have done in the module.