To carry out the internal project work as soon as possible, you have to maintain the control key of an activity in capacity requirements planning. Capacity requirements planning is a process that determines the capacity requirements and availability for work centers or resources that are used to execute project activities. The control key is a parameter that defines the basic properties of an activity, such as whether it is internally or externally processed, whether it requires confirmation or not, and whether it is relevant for scheduling or not. The control key also determines whether an activity is relevant for capacity requirements planning or not. To carry out the internal project work as soon as possible, you have to use a control key that activates capacity requirements planning for the internal activities. Reference: https://help.sap.com/doc/0f069b2e08b748f1b480d4c8b46c3c49/100/en-US/6a7a9f0a6e421014e10000000a174cb4.html