Can I add layouts to a collection page? 

Similar to ‘home’ collections and section collections, Collection Pages can also be configured. Follow the steps below:

• Create a collection from the workspace with story type ‘Story Collection’. For example, ‘FIFA World Cup 2018’.
• Add collections to this collection. For example, the collection for can have collections ‘Russia’, ‘Brazil’, ‘Iran’ etc.
• Use the ‘Manage’ button to set layouts for each of these collections individually. For example, ‘Russia’ might be a ‘Half Image Slider’.
• Click on the ‘Apply’ button.
• ‘Save & Publish’ the collection.
• This will have the slug format of 'domain-name.com/collection/collection-name'

(You can check domain-name.com/template-options to see available layouts)