I presume this is not only lens you have? So does your other lenses AF?
If not you might have the camera on MF settings.
Look at the front of the camera where it has AFS AFC and MF toggle and make sure it is on AFS or AFC.
If the other lens AF but won't and it is brand new return it to the shop for exchange.
If it is not brand new eg 5 months old return it to Nikon Maxwell or the country of original sale for warranty repair.
I had a similar problem with my 24mm AFD before. I got the lens fixed by Maxwell for $190, out of warranty.
Also others in this forum might be able to help.
PS I am presuming you are not getting FEE error message on the LCD. If so make sure your Aperture on the lens is set to the lowest value 1.8