To use A or Av…
First set your ISO for the light in front of you.
You can also use your ISO to get your f-stop number where you want it to be.
(Turn the front or back wheel on your camera, depending on your model, to change the f-stop #).
Remember, to get a blurry background, use a large lens opening (smaller number)
To get a sharp background, use a small lens opening (larger number)
Pay attention to the meter numbers and make sure they are not reading too slow of a shutter speed.
The general rule is not to go below 1/60 sec. for still objects. For moving objects you will need to be
1/500 or 1/1000 generally. If it’s a moving object, try to get the shutter speed to go higher by moving the ISO up).
Practice, practice, PRACTICE!