Guides on how to perform a good A/B test

A number of data analyst roles I’m looking at expect candidates to have experience with A/B testing. Not all roles expect this, but if there’s any work you have to do with the Marketing team, it’s basically required.

Does anyone know of some good resources on where I can learn how to do an A/B test? This is obviously easier to do as part of a company with a website that already attracts a lot of traffic. So I’m not sure how I’d approach this as an independent learner.