Once you have installed both Adobe InCopy/InDesign and Transfer Manager you can do a simple system check to make sure everything is installed properly and functional.
Download any document from CtrlPrint (make sure that InCopy/InDesign is not running the first time a file is downloaded) and once InCopy/InDesign is done loading, and all of the menu items appear, check that there is an item called "CtrlPrint" in the top right of the menu bar, next to "Help". If this item appears than the plugins are installed properly.
Note that the plugins are automatically installed by Transfer Manager the first time a document is downloaded from the system. This menu will not be present before that has been done.
InCopy/InDesign should show a menu option called "CtrlPrint" after a document is downloaded from the system:
If you receive a message in Transfer Manager that says, "Error: Failed to locate the application, or install plug-ins" please see the page here.