What are the "idiot's guide to privacy/cybersecurity" things everyone should know?

Hello!
I'm starting a PhD in computer science in September but my PhD is in stochastic Bayesian optimisation so I don't really touch much cybersecurity stuff, but that won't stop people from hearing "Doctor of computer science" and asking me computer science questions that have nothing to do with the research I actually will have done.
So if a scientific laymen were to ask me something very open ended like "how can I keep myself safe online?", what should I …

cybersecurity guide privacy things