I will try not to give spoilers....though honestly, nothing associated with this series has been concluded, so no real spoilers are possible.

Just a few factoids:    this appears to take place after  the events of the Return of the Jedi.    As they talk about the "New Republic"  and the demise of the Empire.

And at first, I thought the Mandalorians were the "league of Bounty Hunters", but that is clearly not the case, as the Mandalorians wear a specific type of uniform...and the "league of Bounty Hunters do not"  In fact, there is a big fight between the Mandalorians and the League of Bounty hunters...when they were protecting one of their own from revenge by the Bounty Hunters. 

The Mandalorian uniform, however, is fairly identical to that worn by Boba Fett.  So, I guess we can assume that Boba Fett was also a Mandalorian Bounty hunter...but I think that is supposed to be fairly rare.    What is not clear is what, exactly, a Mandalorian is.   It does not seem to be a "race"  of people,  as some references were made to various people becoming Mandalorians.  It is also not clear what their purpose is, if any.  They seem to be almost like a Knight's Templar group of that age.   (though, unlike the Knight's Templar, who were dedicated to God....there does not seem to be anything in particular they are dedicated to:  Clearly it was not the Empire, nor the Republic. Besides, the Jedi were more the parallel to the Knight's Templar than are the Mandalorians.   It also seems clear that they are not like a gang of rogues/criminals.   They are not a Star Wars version of Hell's Angels...but they could have some similar attributes.  And while Boba Fett was a clone....it also does not appear that the Mandalorians are a group of clones.  The "lead" role in this....who apparently goes by Mando the Mandalorian, talks about having parents that were killed when he was young after which the Mandalorians took him in. 

I also assume that if you have seen anything at all in this, there is the existence of the "Baby Yoda".   It obviously cannot be Baby Yoda himself, because with the time line, Yoda would have died.  Some have suggested that this is Yoda's clone, because it is very powerful with the Force.  Who knows?   It could just be a baby of the same race as Yoda,  for, while until now we have never seen another creature like Yoda,  obviously Yoda is some certain species, and there have to be others of that species out there.  Fair to say?  

Again, since nothing is really concluded, I will say something about the story:   There is some remnant of the Empire (don't know if this is the First Order or what)  that wants the little green big eared baby for either experiments or to kill it or something. They are the ones that put the bounty on it that  Mando pursued originally.