Following up on this, it's a touchy subject for many because it gets associated with decades of false promises of cold fusion, but a modest NASA lab has produced some fusion reactions with gear that looks like it would come out of your grandpas CNC shop.
The basic idea from what I can put together is that erbium is loaded with deuterium gas (hydrogen with a neutron) until it can barely hold it anymore, and shot with photons until neutrons break off and accelerate other deuterons (proton and neutron) into another one, creating helium-3. Apparently the lattice structure of the metal is the key component to why something so simple works, that the electrons in the lattice screen the deuterons encouraging the reaction.
The key seems to be in the production of the sample:
"A metal such as erbium is “deuterated” or loaded with deuterium atoms, “deuterons,” packing the fuel a billion times denser than in magnetic confinement (tokamak) fusion reactors."
It seems once the sample is prepared, seems relatively simple to produce energy from. On looking a little further, I found this that seems to be a precursor a few years ago:
It looks like they just blast the metals with a deuteron beam for a few hours.
I think my favorite part was looking at this video. Seeing useful results produced from such seemingly simple methods and equipment is a lot more impressive than the massive multi-billion dollar projects that catch headlines: