Press the Windows key + I key to get into the Windows settings. From there select Mixed Reality > Startup and Desktop, and de-select "Start Mixed Reality portal when my headset’s presence sensor detects that I’m wearing it. On the same screen under “Input Switching” click the drop-down and select Manually switch using Windows logo key + Y.
Basically, as I mentioned last night in my boot-up steps, load your game, create your flight plan and load into the game. Once you are in the game, press the start button (if on a controller) or esc key (on keyboard) and go to general options I think > select VR (which is the last category in the section) and select switch to VR.
One other setting I changed, but I do not know if this made much of a difference, but under the Mixed Reality section > Headset Display, under “Adjust level of detail and quality of effects in the mixed reality home” in the drop down I change it from high to low.