It clearly shows that they are serious about the adventure and that it would be dangerous. They agreed to give Bilbo one 14th of the haul and to cover any funeral expenses if needed.
With Gandalf and the dwarf Thorin Oakenshield, and his company of twelve further dwarves.
The note mentions funeral arrangements.
Thorin Oakenshield, or Gandalf, depending on your perspective.
Bilbo first wished he was back home during the unexpected party at Bag End, when Gandalf suggests that he join Thorin and Company on the adventure. Bilbo is initially hesitant and longs for the comfort and security of his hobbit hole.
Thorin and the rest of his dwarven company
No they are not. Bilbo is simple hobbit from the Shire, Thorin is a dwarf.
Bilbo Baggins was famously a hobbit, not a dwarf.
Bilbo went on an adventure with the thirteen dwarves, Fili, Kili, Balin, Dwalin, Dori, Nori, Ori, Oin, Gloin, Bifur, Bofur, Bombur, and Thorin Oakenshield, and Gandalf the Wizard was with them some of the time, too.
Bilbo takes possession of the Arkenstone without telling Thorin.
burglar
Bilbo took the Arkenstone. It was the treasure Thorin desired most.
When Thorin learned of Bilbo's treachery he kicked him out and said that the 1/14 share promised to Bilbo would be used to buy back the Arkenstone. He figured Bilbo would get little of it.