You must select the Enable Distributed Testing check box to distribute a test. Once enabled, the rest of the fields on the Distributed tab are activated.
The check box is not enabled by default on new tests. However, once you have set up a distributed test, if you save and close a test with the check box enabled, it will reload in the enabled state.
The Main Test node on the Test Browser indicates if your test is set up to be distributed. For example, if you have a distributed test containing 60 iterations, the node displays Main Test (60 Iterations) – Distributed, as shown in the following figure.