I just finished my taxes today, involving four K-1s from investments in crowdfunded real estate. The instructions that come with the K-1 should tell your what forms you'll need to fill out based on what boxes on the K-1 have data in them. The only tricky part I found was where it referred to "See the Partner's Instructions." It turns out there are multiple Instruction publications for Form 1065, one of which is "Partner's Share of Income, Deductions, Credits, etc." Those instructions gave me everything I needed, though I will say it was confusing at first. For me it resulted in filling out Form 8582, Schedule E, and Form 4952. Though I think that last form is useless in my circumstance because the K-1 didn't give me enough data to complete the form. I believe it was meant to contribute to other data if the form was already being filled out.