How to install module/plugin on Joomla administrator?
Firstly you have one web-site use Joomla and installed redSHOP component. Access your web-site by administrator page by (username/password) has been provided

Secondly click on Extensions then select "Install" in main menu
Install page display
Module redSHOP newletter has downloaded before
After install success webpage will show message "Installation of the module was successful."
Click on Extensions on top menu and select "Modules"
Webpage will show all module items in this page. User select "newsletter" in field search then click on icon search button
Webpage show on items redSHOP - Newsletter items and click on it