I assume they shoot the fuel in with some light particle acceleration. Maybe they just let it diffuse in, but it's a gas so it's not that hard to get it to enter.

The hope is they get the cost of maintaining the electromagnets (power and cooling) to be cheaper than the power we can extract from the reaction.

My question is more about what's the logistics of getting power out? We're making a lot of heat, so it's probably steam power at the heart of it, but a lot of this effort is to keep the heat in is it not?