Watch the original series and/or the Next Generation. Don’t bother with the movies until/unless you become a fan, as they’re not relevant to anything in the TV series, but you do need the series to understand the movies. Skip season 2 of TNG. Nothing remotely interesting happens, and it’s one of the worst seasons of the 43 years of Trek history. Move on to DS9 if you enjoyed TNG. Move on to Voyager and Enterprise if and only if you became such an incredible fan that you just HAVE to see everything with the words “Star Trek” in it. They are otherwise completely skippable.