Reading the book it seems the main way you conjure, invocate, I don't know, is by speaking certain passages. The circle is protective, you stay in the circle while you do this because the demon cannot enter the circle. The seal of the demon seems to confer power over the demon, I believe you can show it to the demon to make it submit, but it is also to be inscribed on the backside of the pentagram of Solomon, which is supposed to be part of why the seal grants power over the demon (I may have misunderstood, it may be the pentagram that confers the power and the presence of the seal on the back makes the pentagram specifically effective against that demon.) If the seal in and of itself summoned the demon then just printing the book, having it on your bookshelf, or whatever would bring a ton of demons into your vicinity, and nothing in the book seems to indicate this, and I imagine magicians would have warned us against keeping the book without some sort of procedure to prevent this. I would still say don't tattoo these seals on your body. (fucksake)