These are the shows in order of release and how you should think about them:

Before you get started, just watch the movie “Star Trek: First Contact”. It’s a good place to start. If you like that, then...

Star Trek (also known as Star Trek The Original Series or Star Trek TOS): 60s TV show. Worth watching later if you fall in love with Trek. But you can skip it initially.

Star Trek: The Next Generation (otherwise known as Star Trek TNG): 90s TV show. Gets very good by season 4. I’d start here if you can tolerate some late 80s and early 90s tackiness. This show sets the tone and firmly establishes the ideology for modern Star Trek.

Star Trek: Deep Space Nine (otherwise known as Star Trek DS9). A darker, more serialized and more sophisticated show. Its set on a space station instead of a space ship. It pressure tests the ideology that is set up in TNG by confronting it with the realities of politics and religion and living with consequences when you’re stuck in a dangerous environment on the fringes or Federation space. Avoid this until the end if you really love trek.

Star Trek: Voyager. A fairly modern show that still holds up well. Initially intended to pressure test the ideology of TNG by confronting it with the reality of being stuck on the other side of the galaxy with no backup and a 75 year journey home. Quickly and mostly abandons that premise for fun adventures. Easy viewing. Start here if you want something more accessible and easy to digest.

Star Trek: Enterprise. Prequel show. Shows the first proper adventures of humans going out into space with a warp capable ship - soon after the events of Star Trek: First Contact (the movie you just watched). Don’t bother right now. Pretty weak.

Star Trek: Discovery. Still being made. Very flashy. Not really authentic to the original spirit of the show. More shooting and less talking.