Step 1:

Download the module to your desktop.

Step 2:

Log into your Prestashop 1.5 Dashboard.

Step 3:

Using the top menu bar, hover over the Modules tab and select the Modules option.

Step 4:

Then click on Add a new module button on right hand .

You will see a box for uploading your module 

Using the Browse button, locate the module from your local computer. Once selected, click the Upload This Module button underneath the Module File field. This will upload the module to your PrestaShop Module API. Once you see the successful message, you know the module is added correctly.

Step 5:

Find your module on list modules, then click Install button on right hand of this module row.

And you installed module successful