Under Recommended releases, download the zip file for your Drupal version.
The following steps describe how to install the Ubercart module on Drupal 7. The exact steps for Drupal 6 differ slightly, but are similar.
Log in to your Drupal site as the administrator.
On the top menu bar, click Modules.
Click Browse, select the zip file on your local computer, and then click Install new module. Drupal installs the Ubercart module.
After installation is complete, click Enable newly added modules.
Scroll down to the UBERCART - CORE section.
To enable the required components, select the check boxes.
If you cannot select a check box, this means the module depends on another module that is either missing or disabled. For example, Ubercart requires the CTools, Entity, Rules, and Views modules as well.
Repeat steps 7 and 8 for any additional Ubercart modules you want to enable in the following sections:
UBERCART - CORE (OPTIONAL)
UBERCART - EXTRA
UBERCART - FULFILLMENT
UBERCART - PAYMENT
Click Save configuration. After Drupal enables the modules, the Store link appears in the top menu bar.