smokinbuck, you nailed it, for anybody with that same question.
Home Dept
-Tool Section
-Tapered (wood)Drill Bits
-Usually in sets of 3 sizes (Sm-Med-Lg)
-and usually with adjustable Depth Stops
Anchor horn securely so you have use of both hands (don't ask me how I know)
-Drill your pilot hole (can be tricky, so follow horn tutorials on this part)
-Open up with slightly larger drill enough to get tapered drill tip/shank comfortably inserted and
aligned
-Drill slowly utilizing handheld/battery operated drill at very low speed to avoid bit binding and
twisting (please see first 'don't ask me how I know')
Use tapered drill bit as a visual (make slightly larger) guide for plug and you're home-free. Good luck!!