With the 22/4 alarm wire that you are referring to you only need to utilize 2 of the wires.  I would say for simplicity sake to use the red for positive and black for negative.  They will attach to the purple (positive) and gray (negative) control cables on the PTZ.  So the red and purple cable would be combined and the black and gray cable would be combined at the PTZ.  Then you would take the red cable from the alarm cable and connect it to the A in the back of the DVR in the RS485 control block and the black cable would go into the B of the same block.  The other 2 cables (white and green) will just be left to do nothing, you can cut them back or just keep them pinned out of the way.