I’ve driven through a couple snowstorms recently. Last week in the northeast, and then over the weekend in Quebec City where it snowed, froze, and then more snow fell on top. I used 4A and Slippery mode, and it handled everything well. Just drive slow and don’t get overconfident. The Bronco will take care of you.
Slippery mode will put you in 4H automatically. If the roads are just wet, stick with 2H. If you’ve got 4A, use that. If not, use 4H when needed.
Has anyone checked the owner’s manual for the official recommendation? I personally use 4A. If I’m on a dirt trail or snow-covered road, I’ll switch to Slippery for softer throttle response.
I usually keep my tire pressure around 28-30 psi for better grip in the snow. If you live somewhere that gets a lot of snow, get tires with the three-peak symbol.
Slippery mode isn’t that useful unless you’re off-roading. For everyday driving, 4A works great. Right now, I’m out here pulling people out of snowbanks after we got over 24 inches of snow!
Just put it in Slippery mode and 4A.
Slippery mode is cool and all, but have you tried Baja mode yet? 
Slippery is basically Eco mode with 4A. I usually use 4A. My wife likes Slippery mode. It seems to slow the turbo response, probably to avoid wheel slip when you first hit the gas.