The Hobbit features thirteen dwarves that make up Thorin Oakenshield's company:
Fili and Kili--These two brothers are the youngest in the company. Thorin is their uncle; he is their mother's eldest brother. Fili and Kili both are killed in the Battle of the Five Armies defending Thorin with "shield and body" (261).
Bifur and Bofur-- Bifur and Bofur are brothers and were descended from the dwarves of Moria but were not of Durin's line.
Bombur-- Bombur is the fattest of the dwarves. He accidentally falls into the dark river of Mirkwood and falls into an enchanted sleep. Bombur is also a brother of Bifur and Bofur.
Dwalin-- The first dwarf to appear on Bilbo's doorstep at the beginning of the story. He and Balin are both descended from the House of Durin and are remote cousins to Thorin.
Balin--One of the oldest dwarves in the party, Balin returns with Gandalf at the end of the novel some years later to visit Bilbo at Bag-End. He is Dwalin's brother. Balin later goes to Moria. His tomb is found by the Fellowship during their journey through the mountain.
Oin--Oin is also descended from the House of Durin, so they are also distant cousins to Thorin. He and Gloin are brothers and are first cousins to Balin and Dwalin.
Gloin--Gloin originally doubts Bilbo's skills as a burglar, saying "he looks more like a grocer than a burglar" (18). Gloin's statement actually goads Bilbo into wanting to join the company. (Gloin's greatest significance is that he is Gimli's father (Gimli later becomes one of the Nine Companions in Lord of the Rings).
Dori, Nori, Ori--All three are brothers and play the flute. They are also of the House of Durin and are more distant kinsman of Thorin.
Thorin--Thorin Oakenshield II is a direct descenedent of Durin. He is the heir to the Lonely Mountain and the leader of the company of the dwarves. Extremely proud of his heritage, Thorin's deepest desire is to rebuild the greatness of the Lonely Mountain.
If you are referring to the group of dwarves that specifically appear in the Hobbit, a.k.a. Thorin and company, the are part of a sort of diaspora of a dwarf kingdom that once dwelt in the Lonely Mountain. The dwarves (or dwarfs, in some editions) of Middle Earth are modeled on the Northern European dwarves of mythology. They are miners and metal workers who were originally "created" by one of the Valar, or god-like beings dwelling in Valinor. Thorin and company were part of the Lonely Mountain kingdom that was attacked by the dragon, Smaug. Dragons in Middle Earth love to steal and hoard treasure. The Lonely Mountain kingdom was particularly wealthy. Thorin was alive at the time of the attack. (Dwarves live quite long, though not as long as elves.) Some of the younger dwarves of the company are descendants of the original community. Their goal is to reclaim the treasure from Smaug, thus their need for a burglar. Gandalf is guiding them in their plans, so, of course, the idea of a burglar was probably suggested by him.
Elves and dwarves have a long history of animosity. Elves are the first race of beings and were created by Illuvatar, the Creator God of Middle Earth. Even the Valar (who are actually more like angels helping out with creation) were created by Illuvatar. You can see that Elves might feel a bit superior. They wrote down the history/mythology and portrayed the dwarves as evil and greedy in the early works. This animosity is demonstrated in Thorin and Company's encounter with the Wood Elves of Mirkwood.
Thorin is the direct descendant of the king of the Lonely Mountain and is therefore a king in exile. Some of the others, such as Kili and Fili, are his relatives.
As far as physical features, dwarves are shorter than men, larger than hobbits, beared, and quite fierce in battle.
Hope this helps. By the way, Men were the second race created by Illuvatar.