Um... I’m bad at explaining, but...
to summarize all the series,
original series: basically exploring. Can get kinda dull at times, but there are some good episodes (one of my personal favourites is The Trouble with Tribbles )
next gen: also exploring. Generally gets better after the first season. There’s a recurring character called Q. He’s awesome
deep space nine (ds9): serious departure from form; takes place on a space station and waits for adventure to come to them, though they get a ship later. There’s a little bit of semblance of a plot, but not really. (not Star Trek, but I also recommend Babylon 5. It was airing around the same time as ds9, and has some similarities (like having a space station), but it has an actual plot. It’s also REALLY GOOD)
voyager: they’re lost in a very far away part of the galaxy and need to get home. Not much else plot. They actually have to cooperate with a rebel group that they got lost with, which is neat. Captain is female!
enterprise: takes place long before the original series. Don’t know what else to say about it. It’s alright
discovery: takes place a bit before the original series. Actually has a plot! Second half of the first season is really violent, apparently (didn’t watch it). Second season was GREAT! Main protagonist if the series as a whole is a black woman, and she’s not actually the captain or the first officer! Lots of original series references! Sound effects from the original series! Characters from the original series! And it’s great!
...anyways, if you want to know more, I recommend just looking it up on google or something. The internet can explain it WAY better than I ever could
(and, I am not a sensei and never could be x3)