It's such a broad hobby that there isn't really a least common denominator. The easiest way to get into it is probably voice chat on VHF — a cheap Baofeng brand handheld radio and a license will get you on the air and you can decide if you want to spend a few hundred USD on a better radio.

But these days, a lot of stuff can be done using cellular+internet that used to be the domain of hams. Voice comms can be fun (the local repeater nets kept me sane during pandemic isolation) but they're not exotic any more. The other corners of the hobby are kind of esoteric. It's hard to say what might interest you.