These days, without knowing more about preferred programming language or the purpose of the implementation, I'd probably start by pointing to this very thorough series of blog posts by Eric Lippert, from LifeWiki/Tutorials:

  https://conwaylife.com/wiki/Tutorials/Coding_Life_simulators

Life simulators have been coded in so many different ways, in so many languages, by so many different people in the last half-century ... that it takes several dozen articles to work through a reasonable survey of the possible ideas and methods.