Landing Templates are designed to be a natural start of your visitors journey, but can be used for any page that need to distinguish itself from the rest of your content.
Archive Templates mainly include lists (loops in TheDock) of items from collections in your content (Post Types in WordPress). A collection is a group of content that share templates (look), such as Items, Articles, Case Studies, Team Members or any other type of content your site includes.
Single Templates has been designed with the intention of presenting content, on item at a time. Any one of these templates can be used for any type of content, including your pages.