Usually, opencart 1.x modules are being distributed as a zip archive with the upload directory inside. This folder contains all the files of the module. 

Step 1

Unzip the archive and upload content of the uload dir into root dir of your site using an ftp-client or other file manager.

If the module contains a vqmod modification, you should place it into the folder vqmod/xml/. Of cource, the vQmod should be installed.  

Step 2

Go to System -> Users -> User Groups in admin area  and set up permissions to group of administrators and/or other groups.

Step 3

Go to Extensions -> Modules in admin area to install and set up the module.