Follow up after career fair

Hi, how is everyone?

A little over a month ago I attended a career fair and impressed one of the reps from a company with my knowledge about their firm (I did my research ahead of time). They told me that they would be starting their summer internship process in a month and that I should contact them in a month if I don’t hear from them by then.

I was just hoping for some tips as to how I should go about doing this. Should I email or call the rep? What general guidelines should I follow? I don’t want to over think it, but don’t want to dive in headfirst not knowing what to do either.

This opportunity is in a field that I’m really interested in and I don’t want to mess this up. Thanks for the insight!