How does Fusion Energy work and is it a good idea?

Fusion power is energy generated by nuclear fusion. Fusion reactions fuse two lighter atomic nuclei to form a heavier nucleus. It is a major area of plasma physics research that attempts to harness such reactions as a source of large scale sustainable energy. Fusion reactions are how stars transmute matter into energy. [Source]

[Source: Kurzgesagt – In a Nutshell on Youtube]