combining rental properties into an enterprise for QBI safe harbor

Hello.  I have 4 residential real estate properties.  I've reported them in TT for many years.  

I am confused about how to combine these properties into an “enterprise” in order to qualify for QBI safe harbor. I’m also unsure how/whether to report them as a combined or aggregated business.

I’ve gone through the questions for each property multiple times in different orders, and I am never able to combine them all into one enterprise.  The questions also seem to differ for different properties, and I can’t figure out why.

Last year, I think a turbotax expert I spoke to over the phone had me delete forms in order to combine the properties.  But I can’t reach anybody who will help me do this this year.  

I have some carried over losses and I want to be be consistent with prior years.

Any suggestions?

Thanks