If you want to add a module in Zikula then you can follow the following steps :
Step 1 : Search the desired Zikula modules you want to install for your website in the Zikula Modules Database.
Step 2 : Once you find the modules, upload those modules through your FTP client to the modules folder for your website.
Step 3: Go to your site and enter the Admin area.
Find the module which you uploaded and want would like to install from this list. Click on Activate. The selected module is now active.