Reverse Hybrid table

[ZaraS]

Hi amazing community
I have watched this video but I don't understand how the partitions are created in Power Query.
https://www.youtube.com/watch?v=Hpx52kOodPc
I'm trying to create a reverse hybrid table(old data on direct query and import last 3 months). I don't want to use tabular editor and trying to do it in my power bi dataset. 
Does anybody have a sample pbix file or can explain to me how to achieve this?
TIA

[Broderskap777]

Hi, were you able to solve this? 

I am facing a similar issue, i would like to have me old data "cold", i.e direct query mode and new data "hot", in import mode. Lets say my import data is 3 months, I would also want to be able to incrementally refresh that data. Any ideas on how to do this?