How to Install vQmod
Modifying OpenCart core files greatly reduces your ability to upgrade your store to a newer version, and can affect other modules and extensions. vQmod provides a mechanism for modules requiring OpenCart core modifications can be installed without damaging the integrity of your core system for upgrades. vQmod keeps a list of filenames and changes required, in the form of one XML file per extension. These changes are then created as the core files are used, and the resulting files are stored as cached copies which are executed instead of the original, core PHP or TPL file.
The vQmod free download can be found here: http://www.opencartexpress.com/vqmod-for-opencart.
Although not required, we highly recommend you also install vQmod Manager. This allows you to view the installed vQmod modules in you cart and if any vQmod errors are being reported. You can get a free download by going here: http://www.opencartexpress.com/vqmod-manager
Once you have downloaded the appropriate vQmod zip file provided in the link, you need to uncompress the zip file and FTP the vQmod folder to your site's root directory. From the Filezilla screenshot below, we can see the root directory of this store is located at public_html/opencart in the Remote site side. Uploading the vQmod folder here will make the vqmod folder visible in public_html/opencart.
Make sure the permissions are all set to writable for the vqmod/vqcache folders, index.php, and admin/index.php. In Filezilla you can right click on a file or folder, select "File Permissions...", and enter 755 or 777 in the "Numeric value" to set it to writable.
The next step in installing vQmod is to navigate to your stores home page and install vQmod. Example: www.yourstore.com/vqmod/install The following text will appear on the page if it was installed correctly: "VQMOD HAS BEEN INSTALLED ON YOUR SYSTEM!".
Refresh your homepage to see if it is working correctly after the installation. You should also check your vqmod/vqcache folder to see if there are new vq files.