How to place acan coral?

[OpenOcean33]

I bought a small acan coral colony from my LFS. I usually buy frags so I'm not sure how to place this coral. The back side is a straight cut and feels "boxed off" flat. Do i just putty it to another rock and it will some how encrust? it seems like a large gap to cover or can I lay it in the sand bed as is and it will grow? Sorry for bad photo quality. Also you can not see the sharp edge back on this photo.

 

[Retro Reefer]

It will do best on your sand bed just as you have it.. nice piece BTW