I have just installed the TerraClassic theme, looks great. However, when I'm on the main page, and I click on any advert page it opens but at the top, I still have the categories and last ads list. How can I make it to show only the ad? 


The latest ads and categories are TerraClassifieds widgets and you can disable them using plugin AH Display Widgets. Use this plugin to take control over widgets in a theme. 

At the bottom of every widget settings, you will find this area that helps you control where it should be visible: 

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