There are three layout options for the collection pages.
Collection description centered
Shows the collection title and description in the center of the page, with a product from the colletion either side.
Collection description in sidebar
The collection description is shown in the sidebar, with the products to the right.
Hide collection details
The collection description is hidden, and full emphasis is on the products.
'Enable sorting' shows a dropdown box of all of the options to sort the products, such as 'price', 'date added', etc.
'Enable tag filtering' allows you to show a dropdown of all product tags, which customers can then use to filter through each collection.
'Enable infinite scrolling' ensures that if there is more than one page to your collection, when the browser reaches the bottom of the page, it will continue to scroll without having to click 'Next'.
'Enable quick shop' shows a 'Shop now' button, which allows customers to view the products without going to the main product page.
Enabling this option will set a height for each product, a great way of getting your products to line up if they are different aspect ratios.
If you are using the free Shopify app, Product Reviews, ticking 'Enable' here will show a star rating on each product.