The GatherContent AEM connector is delivered as a package. The following steps should be completed to install it:
Go to the AEM package manager
Verify package installation log and status
Multi-Site Manager (MSM) Support
Most of Multi-Site Manager actions are based on 'last modification date' changes. This date changes automatically by 'Repository Change Listener'. Please make sure that your listener is watching your imported content.
So if you are going to import the GC content under '/gccontent/sites/my', go to '/system/console/ConfigMgr and add your new path in 'Day CQ WCM Repository Change Listener' properties.
At the same time, the GC plugin marks imported pages with special technical properties: GCItemId, GCMappingPath, GCProjectId, isGCImportedPage. These properties associate your GC content with AEM content. If you going to use any of MSM features with imported content, please avoid duplication of these properties. You can do it with 'CQ MSM Content Copy Action' and 'CQ MSM Content Update Action' in your configuration console '/system/console/configMgr': just add the above properties to the 'Excluded Page Properties' list.
If you have previously configured MSM for projects imported using gathercontent.ui.apps-1.0.12 build or earlier version then you have to delete MSM copies and create them again (primary branch, i.e. blueprint)"