OK, at this point you should clean it up better than I did. The flash I used for the photo ratted me out - I didn't see how much debris I actually left behind under the bike in the garage. You want this squeaky clean because you're about to drive a steel insert into these fresh aluminum threads and this is a one-way trip and you don't want it to bind or hang up as you insert it. Clean the threads, the case, your hands, the tap handle. Start clean.
Now - this is the insert that's going in. Notice that it has a shoulder on the left side. That's what is going to sit in the chamfer that we cut, and that prevents the insert from just screwing in and potentially through the borehole. If you look really sharp you can see that on the other end of the insert the very tip is a bit smaller than the body. That's going to expand when the insertion tool pushes through it, and that locks it into place. Ingenious, elegant system.
Now, oil the insertion tool as the instructions indicate, insert it into the... insert, and commence to insertin'. I'm almost done here.
Now, this is important: Once the insert is bottomed on the chamfer, you have to continue screwing the insertion tool in for a few turns. You will feel some resistance as you are pushing against those smaller threads at the tip of the insert. The tool will force those last few smaller threads out to lock them into the borehole. Once the resistance is past, remove the insertion tool and you're done.
Insert your new drain plug, REPLACE THE OIL AND FILTER IN YOUR MOTORCYCLE and pop a beer: