The Relay Control panel allows you to quickly swap runners and commentators on your layouts. The graphics don't have space to list multiple runners on a relay team, so what you can do instead is have the other runners listed as commentators, and then when the first runner is finished, swap them with one of the commentators.
Using this setup means that for a solo run you can have a maximum of four runners and/or commentators (the host cannot be swapped). The Relay Control also works with races, however all teams still share the same pool of three commentators.
Alternatively you can use the relay control to leave the commentator details as they are, and just swap between your runners. Using this method would let you have three separate commentators, and the runners in waiting aren't displayed on the stream. The panel is fairly versatile, so its worth experimenting to figure out exactly how you want to use it.
The Relay Control panel will only activate if the current run has the "Relay" checkbox ticked in the Run Editor. However you intend to use the Relay Control you still have all runners set up as runners in their teams in the Run Editor. It's then worth duplicating the runner details into the Commentator fields in the configuration you'd need them for the start of the run.
The panel shows a list of the runners in each team at the top, with the radio button declaring which is the current runner. Below are the commentator fields, showing what details are currently being shown for each - these can be edited to prepare new details. Ticking COPY RUNNER allows you to use the dropdown on each to select one of the runners to send to the graphics instead of what's entered in the commentator fields.
Changes you make on the panel are only sent to the graphics upon clicking UPDATE SPEEDCONTROL. Therefore, once a runner has started, you then want to queue up the next runner: select them in the radio list at the top, and set the commentator details as required. When the runners swap over, click UPDATE SPEEDCONTROL to make the changes - the Commentator fields will then update if the COPY RUNNER list was used instead.
The changes you make in Relay Control are permanent; they do affect the details entered in the Run Editor. If you've made changes in Relay Control you will either need to use Relay Control to change them again, or edit them manually in the Run Editor.