How to use Nvidia On-Demand option?

I've been trying to switch over to Linux for a while but as someone who has a heavy reliance on good battery life, I've always had trouble. After looking at the 19.10 release notes, I was really exited to look into the on-demand options. The only thing I use my dGPU for (on Linux) is my monitor, as when I disable it through Intel mode, I can no longer connect to it. My hope is that I can enable the dGPU solely for being able to use my monitor, while doing all the processing on my iGPU. Unfortunately it sounds like you need to configure this and I'm not quite sure how. I tried looking at this but couldn't quite understand it. (my laptop is a Lenovo P1 1st gen)

So after doing more research, it looks like the proprietary divers don't support reverse PRIME, which is what I need. It seems like nouveau supports this but the problem is I can't find any articles of how to set that up. Does anyone have more info on this?