With autofocus turned off, the camera does not focus for you when you half-press the shutter. You must turn the focus ring on the lens yourself and judge focus through the viewfinder.

If many focus points appear lit, it can simply mean much of the scene is within acceptable focus. That often happens with a kit lens, wider focal lengths, and subjects that aren’t very close, because depth of field is large.

To get more background blur:

• use the widest aperture available (lowest f-number)
• zoom to the longest focal length on the kit lens
• move closer to the subject
• keep the background farther away from the subject

Then manually turn the focus ring until the nearer subject looks sharp. A faster lens with a wider maximum aperture can make this effect stronger, and larger sensors can help too, but with your current lens the biggest gains come from getting close, zooming in, and opening the aperture wide.