It doesn't look all that difficult to do. It involves the creation of an electrically induced plasma between an inner and outer wire ball electrode in a rarefied deuterium gas. The toughest thing seems to be to get and hold a hard enough vacuum for long enough in the system to purge it from other substances that will interfere with the deuterium plasma.
The fusion yield isn't anywhere close to the break even point, but it can emit some serious radiation.