Just to add to pdamm comments. I have one of these tools in my toolbox but normally I set the rotation / chain tension by hand rotating the EBB. Personally I find it quicker and even easer to do it this way that to use the spanner!
One positive feature of the spanner is that it is that it is a little bit shorter than the average 15mm spanner and therefore has a little less leverage. This is a good thing as you don't need too much torque on the EBB bolts.
Adjusting the EBB is VERY easy. Much easer than it looks! I would say that it is about as difficult as setting the height on a seat post. Everyone things it is difficult until they have adjusted it.
Rules for adjusting the EBB
1. Make sure the thicker part of the EBB is closer to the bottom than the top of the BB shell.
2. Don't mussel the bolts
3. Don't over tighten the chain. Better the chain is slightly loose than too tight
4. Put some copper grease on the EBB / BB shell interface (to avoid the EBB seizing)
The job takes less than three minuets, once you are practiced.
For some more info look on pages 10 and 11 of the manual