On the main screen one can open the configuration of the controls with the icon :

In the example above there is already a configured control with the name "My Control".

At the bottom there is a button named "New" to add a new control to the configuration.

Usually there is only one control per model railway layout. For bigger layouts it can make sense to use more then one control, so there is one control for the locomotives, one for the accessories and one for the feedbacks.

Actually RailControl supports the following controls:

Manufacturer Control
CAN-Digital-Bahn CC-Schnitte 2.1
Digikejis DR5000 (configure as Roco Z21)
ESU ECoS/Central Station Reloaded
Fleischmann Twin-Center
LDT HSI-88 RS232
Märklin Central Station 2/3 with TCP (new)
Märklin Central Station 2/3 with UDP (old)
Märklin Interface 6050/6051
OpenDCC OpenDCC Z1
Roco Z21/z21
Tams MasterControl
Tams MasterControl 2
Tams RedBox
Uhlenbrock Intellibox