The basic rule looks something like this:
Manual, Sunny - ISO 100, f16, 1/100s
Manual, Overcast - ISO 100, f8, 1/100s
For Av, just go by the above. But when in doubt, overexpose. It is easier in PP to pull it back than it is to add missing detail that doesn't exist when underexposed.
You're thinking "if I open up the apertue, I can blur the background". Sorta. Yes, for every stop you open, you double the shutter speed. But "blurring the bakground" means more.
Ignore the camera settings. What you need to be concerned with is (1) distance from camera to subject, (2) distance from subject to background, and (3) focal length of the lens during exposure. Yes, you want a large aperture opening but moreso you want to be close to the subject and have them as far as possible from the background. More telephoto would be better than less, with WA not in consideration. If you're talking a kit lens, you'll need to work at this.
If you want the geek aspect of this, search circle of confusion and depth of field. There are lots of DOF calculators that will help you estimate.
OP, I'm curious where you plan on shooting. Not Main Street, I hope. Everything is way too close there. Pick your location carefully to maximize the background distance and get the background of your choice.