Investors & landlords

OK, I got to the Disposition fields, and my 1099-S does not provide the information in the format they are asking
Assett Sales Price
Assett Sales Expenses
Land Sale price
Land sale expenses

There is no where to deduct the mortgage I paid off. I had to look at the tax records for the break down. And if I don't put anything in the expense field (would the mortgage be that) The taxes seem extremely high. 
Plus, this was owned 50/50 between myself and my uncle. -Do I cut everything in half for each tax return?