The kilominx is just a two by two megaminx. On the kilominx I have, there are centers that don't move. That is different than a 2 by 2 though, because 2 by 2 cubes aren't supposed to have centers. They are colored, so it would look weird if you put them in the incorrect place. You DO NOT want to get the cube shown, because it has centers. There are red edges, as you can see, but because they are all red it doesn't make a difference where they are. The colors are the same opposite as with the megaminx. ex. gray and white.
On Amazon a stickerless kilominx is $11.88 but it has centers, so is technically not a 2 by 2 megaminx. A kilominx with stickers, but doesn't have centers is $10.88. I would get the one with no centers. You DO NOT want to get one like the cube above, because it has centers, and trust me, that is bad. I only got one with centers because I didn't know this.
The 3 colored pieces in the corner area of each side are corners. They are the only pieces besides the centers which are the circles in the middle. As stated earlier, kilominxs aren't supposed to have centers, so most kilominxs won't have center pieces.
You solve the kilominx like a megaminx. You first solve the white side and first layer like a 2 by 2 Rubik's cube. Then, you get the second layer a different way than the megaminx. You then get the last corners like on the megaminx getting the first 6 sides. You then skip the gray edge steps and position the corners on the gray side like the megaminx. You then twist the last layer corners just like the megaminx and the 3 by 3.