The Phase selection options let you choose the phases of a Deploy Job you want to run. You can also choose how to stage the deployment.
In the phase selection options, staging refers to how packages are delivered to targets without actually applying them to those servers. (A package does not necessarily include source files if you are using a network-based deployment.) You can stage packages directly by pushing the packages to targets, or you can stage indirectly. When staging indirectly, packages are pushed to servers designated as repeaters, and then the repeaters push packages to multiple target servers simultaneously.
Phase selection options
Perform a test run of a deployment without deploying a package. A test run lets you review job results, see the server objects that are changed during deployment, and determine the actions that cause the deployment to fail.
Apply the package to a target.
Deliver the package to a target.