What module creates after installation?

Usually modules must be configured before its first usage. Product list quantity discounts is also an addon that must be confgiured. Addon does not create many configuration sections in shop's back office where you can manage its settings. All the settings of the module and its workflow are available on its configuration page:

What module does after its installation?

Module installation does not create only configuration page of the module. During installation process module is associated with hooks (hook is a position where prestashop allows to run modules). These associations are required for this module. You can find list of associations here:

• displayFooterProduct
  to display module on product page in product's footer section (bottom part of product page)
• displayProductAdditionalInfo
  to display module on product page below "add to cart" button (the exact position of hook depends on theme - especially on how the theme developer included this hook to theme).
• displayProductDeliveryTime
  to display module on list of products below each product cover picture. This is default hook in prestashop 1.6 and optional hook in prestashop 1.7 (not always included, but some themes still uses it)
• displayProductListReviews
  to display module on list of products below each product cover picture. This is default hook in prestashop 1.7.
  
• actionAdminControllerSetMedia
  to include required css and js files in shop's back office - without this hook configuration page of the module will not work correctly.
• AddProduct
  to clear module's cache when new product is added to shop
• UpdateProduct
  to clear module's cache when product is updated
  
• DeleteProduct
  to clear module's cache when product is deleted
  
• CategoryUpdate
  to clear module's cache when category is updated
  
• actionAdminGroupsControllerSaveAfter
  to clear module's cache when product is updated
  
• actionObjectSpecificPriceUpdateAfter
  to clear module's cache when product is updated
  
• actionObjectSpecificPriceAddAfter
  to clear module's cache when product is updated
  
• actionObjectSpecificPriceDeleteAfter
  to clear module's cache when product is updated
• header
  To include required files in shop's front office. Without this hook module will not work correctly in your shop's front office

as an additional hooks, you can use these positions:

• displayProductListPlqd
  is a dedicated unique module hook to display it on list of products anywhere (within product thumb) you want. Use hook execution code like {hook h='displayProductListPlqd' product=$product} please note that variable $product must exists
  
• displayProductPagePlqd
  is a dedicated unique module hook to display module on product page, anywhere you want. To execute this hook you need to add hook execution code like {hook h='displayProductPagePlqd'}