In order to properly get a blurry photo first you have to get a slow shutter speed. This is because when the shutter remains open for a longer time you get a blurry subject which is what you want. Although because of the slow shutter speed you may have to use a tripod as to not get the entire image blurry.
Like I said in the last paragraph the camera is going to shake because of the slow shutter speed. you are going to want to use a tripod to stabilize it. If you do not have a tripod then a table or bench will suffice. A tripod might be more useful though because you might have to follow your subject depending on if it is moving or not.
It would be much more easier if you used the shutter priority mode. This is so you do not set the aperture or the ISO and make the Shutter speed adjustable by you. Using a small aperture might be more useful as well because it would affect the depth of field making it a bit easier to make the moving subject blurry. Finally, decrease your ISO so that the background isn’t to bright making the moving subject too dark.