If your Kona didn't come with a bracket, then you're going to have to buy one before mounting the actual license plate to the front. Dealerships usually provide one with their location because it's pretty much free advertisement and doesn't cost them much, so you could try asking your dealer for one.
Same here,mine came with a nice bracket for the front plate. Other alternative if you do not want to drill holes into the grill is a side mounted. Attaches through the front tow hook and sits to the side, downside is some states are picky as far as the definition of where the plate should be mounted its more of a gray area in the law also finding the right size in mm for the main bolt .