You can read about setting up applications for displaying in trades here. To display trades of a single application, select it from the list:

Cosmic Dust [Large]
x1
Intralism
Cosmic Dust [Large]
Type: Other
Useful for crafting
Linea, the Game's Lines
Intralism
x0
Linea, the Game's Lines
Type: Skin
Market price: ~0.08 USD