After you have completed the purchase, you can download the extension in its details view for an unlimited amount of time within the SmartStore Community Marketplace. The download will be carried out as a file with the extension .nupkgzip if it is a theme or a plugin. In case of a language pack, you download a file with the extension .xml.
When you've downloaded the extension on your computer, you install it by visiting the admin area within your SmartStore.NET Shop.
Plugins
Choose the menu item Plugins->Manage plugins and click on the button Upload Plugin. Choose the nupkg zip file you've downloaded in the SmartStore Community Marketplace and click on Upload & Install. The plugin has now been installed and can be configured in the plugin management area.
...
Choose the menu item Configuration>Themes and click on the button Upload Theme. Choose the nupkg zip file you've downloaded in the SmartStore Community Marketplace and click on Upload & Install. The theme has now been installed and can be configured in the theme management area.
...