K511 Auto focus

I have bought a Pentax K511. Always had Pentax but this is the first time I have had a digital camera. I do not seem to get the auto focus to work. I have the setting on auto focus but I have to still manually focus it. Have been working through the very thick book they give you but do not seem to know what is wrong. I know the problem is me but cannot work out what I am doing wrong.
Any help appreciated.

As well as the auto focus 'setting' have you turned the autofocus switch on?(located on the front by the lens mount)

What lens are you using? A few lenses have AF/MF switches, as well as the aforementioned selector switch on the camera body,

Look around the camera body, set all switches to green (out of the box default setting) that have a green position, including the 3 position auto focus switch on the left hand side (as you hold it) of the body. Properly fit an auto focus lens and set its AF/MF switch to AF if it has one, and start from there.

If it still doesn't auto focus, send it back to the supplier for a replacement.

I have it set on green mode, on auto focus and at the front on af s for auto focus single shot. The lens that I am using is a pentax lens that came with the kit. I will read further and see what I can do.

Which button are you pressing to focus it? Out of the box it will probably be set for focussing via a halfway press of the shutter button.

Regards
David