That’s always been the top show stopper. Even if the magnetically contained plasma can be sustained, how on earth will useable work be extracted?
You run lithium or other suitable liquid through the superconducting magnets. It hearts it up and in turn is used to convert water into steam. That steam turns steam generators that create electricity
The problem with Fusion has always been how to get more electricity out of the process than you have to put into it in order to heat the plasma and get it going.
Has been this way since the 80s and sti is now. We keep getting closer to the breaka even point but we are still net negative.