There are three layouts you can choose for your collection to be displayed in: 

Media View
Links, images and videos show in full, e.g. videos can be played on the page
 
Compact View
Links are shown as tiles and descriptions only.
 
Grid View
Items are shown next to each other, in a grid.

To change the layout of your collection:

• Open your collection from the home tab
• Click 'Edit' at the top of the screen
• You'll see the current layout under the text 'Collection Layout'. 
• Click the current layout. 
• Choose a new layout. The popup will close. 
• Click 'Save' at the top. 

And that's it!