Installing a theme for Magento can be done in 3 simple steps; choose and download your theme, upload your theme, and activate.
Use your favorite search engine to identify the type of theme you want for your site, which in some cases may require you to create a log in for the community, or even purchasing the theme from the provider.
Once completed, you will be given a zip file to extract on your computer. Once you extracted you will see at least 2 folders; “/app” and “/skin”. In some cases, if images are associated with the theme you may have an additional folder named “/media”. For different themes, there can be different folders associated but be mindful the core folders that you want to see will be “/app” and “/skin”. Now these folders need to be uploaded.
Access your site via your favorite FTP client, I am comfortable using Filezilla. Once connected to your server, upload the folders to your root directory. If you already have the folders we specified earlier in your domain directory, please be mindful to put the content of the folder into the corresponding directory. If you simply transfer the whole folder, you run the risk overwriting the existing folder, eliminating what your previous had on your site. Instead compare the content of each pair of corresponding folders, to ensure you are adding your new content without removing current content.
Once new content is successfully added, your final step is to activate your theme. Log in to your Magento admin panel, click on the System drop down, then click on Configuration. This will upload a new page where your will have a menu to the left of your window, click on Design. From the Design menu, you will be able to click on Theme, which will expand that section. Type the name of your new theme into the Templates, Skin, Layout, and Default sections, and click Save Config located towards the top right of the section.
Mission complete! If you revisit your site you will now see your website dressed with your new theme!