How do I create a separate vendor partition?

I recently got an android phone running AOSP Android 5.1 Lollipop. I want to upgrade its software to higher android version, probably 9.0 as per the phone's capacity. But for that, I need treble support in the phone. And for that, I need to create a vendor partition. Here is a tutorial I found on XDA. [Link](https://forum.xda-developers.com/t/guide-project-treble-manual-create-vendor-partition-for-pt-gsi-rom-mi3-mi4.3878995/) This guide is focused on MI3/MI4 devices and the resource ROM mentioned in it is also for MI3/MI4 devices. I think they may not work on my phone. The phone with me is of Micromax Canvas model. So please guide me through this. Thanks.