With the help of the link How Do I Install/Upgrade/Uninstall an AppExchange App, you can easily understand how to install/upgrade/uninstall the app from the AppExchange.
PS: View Drag, Drop & Upload Files to Amazon S3, a Salesforce AppExchange app for moving files from Salesforce to Amazon S3: https://appexchange.salesforce.com/appxListingDetail?listingId=a0N3000000B5ZPqEAN
