The placement isn't all that difficult, but it can be tedious.
The manual (which should be downloadable) from the ML website gives you some general pointers.
Ideally you want to the speakers a few feet from the rear wall and a few feet away from the side walls.
Ideally, for two channel stereo listening, you don't want the speakers next to a large TV or home entertainment center (or other furniture).
You can also adjust the rake angle (back and forward tilt) as well as toe in and toe out. For the rake angle, you can purchase spikes via the ML website or other online dealers. Just make sure the thread size matches the aerius i speakers. You can buy different lengths to tilt them backward or forward. Most people probably buy the one or two inch spikes to get them off the carpet or floor.
For the toe angle, this is totally subjective. Many of us like the speakers toed in a little bit. There's the flashlight technique where you sit on the couch (your sweetspot) and shine the light at the speaker. Basically you want the light to shine in the 'inner' portion of the panel. Do a search (ML's very own Jim Powers gave us this tip). When you shine the light, you keep adjusting the speaker until the inner portion hit the light coming from the sweetspot.
Lastly - there's the distance from the couch to speakers. Some people like the speakers to couch distance to be related to an equilateral triangle. That is to say, if the speakers are 8 ft apart, you should sit back 8 ft. Other prefer to sit very close. Some might like to sit as far back as possible.
Keep in mind that you don't NEED to do any of this stuff. Just try one thing for a little while, toe in say and give it a few weeks and try out some other music. Then toe them in some more, or toe them out - whatever you want to get the desired sound.
The other side of the coin is treating the room. Once the speakers are set, this is by no means the 'end.' You can further adjust the response by adding bass traps and diffusion (or absorption) panels to the room. Most people will tell you that treating the room is probably the biggest upgrade you can make aside from purchasing different speakers and/or different amplifiers.
In my opinion, the main thing to try out (if you have the time and patience) is trying to get the speakers away from the side walls and away from the rear walls. Depending on your layout (and furniture) this is easier said than done. For many people, there's only one or two reasonable speaker locations for any given room that already has furniture.
After that, mess with toe in/out.
Then you can consider spiking the speakers and maybe consider some room treatments.
Erik