Edit: https://en.wikipedia.org/wiki/ITER for visuals.
From the article you referenced:
> ITER will not produce enough heat to produce net electricity and therefore is not equipped with turbines to generate electricity. Instead, the heat produced by the fusion reactions will be vented.
So in a fusion plant, the particle energy would turn into heat (by the particles interacting with matter), this would heat up water (or some other carrying fluid), turning a turbine that produces electricity. See also https://en.wikipedia.org/wiki/DEMOnstration_Power_Plant which contains some diagrams showing just how that would be done.
More exotic reactions (e.g. p-B11) have been proposed, where almost no energy is in the form of neutrons. Theoretically, you could then use electrostatic devices to capture the energy directly without any of the mess with Carnot efficiency. However, getting p-B11 fusion going is much harder than d-t.
The rest of the power gets dumped into the divertor. This is a pretty violent section of the hull that has an enormous power density slamming into it (in ITER it will be similar to an atmospheric re-entry vehicle). There are games to play here though and the strike points can be blown up in size.