Here's are two quick-guides for a step-by-step base/rover setup with Leica Captivate system:  One with Internal UHF radio on the GS sensor,  and one with External UHF base radio with a Internal UHF Rover.

In cases for internal UHF radios bases, although the base or rover sensor can be interchangeable as long the base sensor unit have a internal Satel M3-TR4(+) or M3-TR3(OEM22 or 20), they can be configured to transmit using their internal radio. 

RTK Internal UHF Base Rover Quickguide 

Other configurations/setup can also be used (For example, using a Satel HPR3/4 external radio):

RTK UHF Ext Base Rover Quickguide