We had to file a K-1 this year. However, we have an accountant do our taxes, so I can't tell you any specifics on what you have to do with it. Depending on your income, there are tax consequences associated with the K-1.
To bring this back to a bicycle-related topic: I'm part owner of some commercial property and on paper, we made money. But the partners, including me, didn't actually receive any money. Nevertheless, because of the K-1 I had to pay taxes as if I had received the money -- enough to have bought a very nice Di2 bike.