Here are the Hook Table's:

ps_hook

1. payment
2. newOrder
3. paymentConfirm
4. paymentReturn
5. updateQuantity (Quantity is updated only when the customer effectively places his order.)
6. rightColumn (Add blocks to rightColumn)
7. leftColumn (Add blocks to leftColumn)
8. home (Add blocks to Homepage content mainpage)
9. header (Add blocks to header)
10. cart (Cart creation and update)
11. authentication
12. addproduct
13. updateproduct
14. top (A hook which allow you to add modules to the top of each pages.)
15. extraRight (Extra actions on the product page (right column)
16. deleteproduct
17. productfooter (Add new blocks under the product description on the page)
18. invoice (Add blocks to invoice (order))
19. updateOrderStatus (Order's status update event - Launch modules when the order's status of an order changes.)
20. adminOrder (Launch modules when the tab AdminOrder is displayed in the back Office.)
21. footer (Add blocks to footer)
22. PDFInvoice (Allows the display of extra information on the PDF invoice)
23. adminCustomers (Launch modules when the tab AdminCustomers is displayed on back-office.)
24. orderConfirmation (Called on order confirmation page)
25. createAccount (Called when a new customer creates an account successfully)
26. customerAccount (Will display in the Customer account page in the front office)
27. orderSlip (Called when a quantity of one product is changed in an order or order slip created)
28. productTab
29. productTabContent
30. shoppingCart (Display some specific information on the bottom of the shopping cart page)

In short, When you "Hook into" you are saying use this module in this place in my website. So if you were installing categories into the left_column you would via backOffice>>Modules>Positions>>Transplant a module, chosse the Categories block in modules and hook into Left Column Blocks. remeber however that not all modules can be hooked into all places. 

Understanding Hooks for Modules in backoffice

When you use the "transplant a module" features in the backoffice, sometimes it can be difficult to know what hooks exist and what they relate to in the drop down list (Screenshot below). Hopefully you will see how this drop down list relates to the Hook table above.

Ps_hook_module

This table stores the module ID, the Hook ID and its position

hook_module_exceptions

Exceptions allow you to specify the pages where you do not wish this module to appear. When you make exceptions and save thise in the backOffice, they are written to this database table. These exception pages relate to your core Prestashop PHP pages, such as products.php or order.php so if you has stated to put (hook into) categories in the elft-Column, the categories would appear in the left_column on all pages except products because you have made this an exception.