I entered a K1 twice because of rental and ordinary business income but did not know what to enter and what to leave out:

[JulieCo]

Each box amount reported on your original K-1 form should only be entered one time on your return, even though you are "entering two K-1 forms". 

For instance, on the first K-1 entry, enter box 1 (ordinary business income) and then enter all of the other box information reported on the K-1.  Then on the second K-1 entry, only enter the box 2 (rental income) amount and leave all the other boxes blank.  This way, the total of both K-1 entries into your return is that each box was entered one time.