The Simultaneous Operation step checks for more than one PUT operation running on any master or selected nodes. PUT allows only one operation to run on any master node, and nodes cannot be selected for more than one active operation at a time. When you connect to a PUT-enabled node to run an operation, that node becomes the master node for that operation. Each node selected for an operation receives a lock file containing the pertinent information for the operation that selected the node.
No user interaction is required unless you receive an error or warning message.