In an automation project involving an Orchestrator queue, the Dispatcher is responsible for adding items to the queue, typically using activities such as 'Add Queue Item' or 'Add Transaction Item'. The Performer, on the other hand, is responsible for processing these items. To accomplish this, the Performer uses the 'Get Transaction Item' activity to retrieve items from the queue and then processes them accordingly. Therefore, the correct activity to use in the Performer project is 'Get Transaction Item'.