This part is quite well known and follows the design of classic thermal power plants.
Radiation heat from the fusion heats-up the inner wall of the vacuum vessel. This heats up working fluid flowing behind the inner wall (in case of CFS then plain is to use a molten salt: FLiBe). Also there a second, more important effect: deuterium-tritium fueled tokamaks release 80% of produced energy in the form of high energy neutrons. Large part of energy of neutrons has to be captured by the working fluid for the power plant to be economically viable.
Heat from the working fluid is transferred using a heat-exchanger to heat water and produced steam, which drives a steam turbine and an electric generator.
https://en.wikipedia.org/wiki/FLiBe
FLiBe as a working fluid is not a new concept and has been already demonstrated in molten salt fission reactors.