The following overview reviews the overall steps to add a new shipping carrier.  Individual details for each step will be available in the links below.  You will require all of the shipper's information in order to complete the addition of a new carrier.  This includes the company name, logo, shipping times, zones, acess, costs, fees, and maximum package limits.  The following tutorial will walk you through each step required to make the new carrier available to your customers.

Overview of how to Add a new shipping carrier in Prestashop 1.5

1. Login to the Administration Panel as an Administrator
2. Hover over the menu bar where it says SHIPPING, and then click on CARRIERS in the drop down menu. This will bring you to a list of the existing carriers.  The screenshot below shows the carriers in the test shop:
   
   
   
   
   
3. On the far right hand side of the screen, click on the green ADD button to add a new carrier
4. Fill in the files for the new shipping carrier.  Screenshot below illustrates the fields to be filled
   
   
   
   
5. Once you have all of the fields completed, select the green SAVE button in the top right hand corner of the screen to save your changes.
6. The next step requires that you determine the price or weight range that new carrier will cover.  Select either PRICE RANGES or WEIGHT RANGES from the SHIPPING MENU:
   
   
   
   
7. Regardless of which you select (Price Ranges or Weight Ranges), select ADD NEW to create a new range (price or weight) for the carrier you have created.
8. Select the green SAVE button to preserve the range that you have created.
9. Go to the SHIPPING MENU once again and click on SHIPPING.  Scroll to the bottom and select the FEES section (go to How to set fees by carrier, zone and range in Prestashop 1.5 for further information).
10. Select the green SAVE button to save the fees you may have added.  This completes the overall new carrier addition process.

The addition of a new shipping carrier requires a variety of information in order to be set correctly.  To see more detail on all of the specific steps please refer to the following Carrier information links:

How to set the Shipping Company Name
How to add Shipping Company Logo
How to set the Transit Time
How to add the Speed Grade for a Shipping Company
How to add a Shipping Company's URL
How to select a Continental Zone for Shipping
Selecting the Groups Access for Shipping Carriers
How  to enable Carrier in the Front Office
How to enable Apply regular shipping and additional shipping Costs
How to add regional tax in  addition to shipping costs (United States domestic)
How to include shiopping and handling costs in Carrier price
How to  set default Billing- by total price or toal weight
How to determine Out-of-range Behavior for Carriers
How to set the Maximum package height for Carriers
How to set the Maximum package width for Carriers
How to set the Maximum package depth for Carriers
How to set the Maximum package weight for Carriers

When the process is completed, your customers will be able to select the carrier that they wish to use for the shipment of their purchased product.  Make sure to add only the specific carriers that match your (and your customer's) shipping requirements in relation to the products that you are trying to deliver.