Observe thought without engagement with it. We become aware of ourselves as the observer and the thoughts as mind conciousness chatter and not the whole self. All exercises such as this are developing our ability to clear the mind and maintain focus on whatever we wish without being distracted not getting lost in thoughts. Harder than it sounds but essential prerequisite for this work.
I used to use an exercise in counting from 1 and everytime the mind wanders go back to one. It's useful as it helps us with a sense of progress as we get to higher numbers. You need to be strict though and any distraction start again. At first it will be hard to get past 10 even lol
Another good exercise is visualise a cube and hold it for as long as possible. Again being strict.
PS is this from the Franz bardon book?
I will have a think and go through some of my old books ...but really you can do it without subscribing specifically to one method or teaching system. Better to study a few and just use what works for you to get a good foothold on the path. Soon enough you will be able to work out your own methods as all is in the tree itself and will become clear of you are doing things right, plus you will begin to get teaching from your higher self in dreams and meditations and after a while you won't need a physical teacher at all.
Depends also if you want a purely mystical approach or a practical magickal approach. Dion was a hermetic magician and thus a lot of her work was with the western mystery tradition with lots of practical ritual work.
Very sensible to take your time and not rush into ritual work. It can and will have have far reaching effects on the conciousness. Careful study and analysis of what the rituall actually does is advised but in the end the only way to really know it's to do it... But only when you feel ready. It will also mark the true commencement of your journey into hermetic magick and will certainly bring deep issues to the surface for dealing with so one needs to be ready for this. Engaging the services of a good psychotherapist is often advised for those starting on the path of ritual magick. The LRBP especially lights one up on the astral like a beacon saying.. new initiate over here, so a good understanding of psychic self defense is also useful.
Not to sound ominous but it's often only then that the initiate realises magick is very real and works powerfully.
There is really nowork in this exercise. it is simply as it states, watch the thought,don't interfere with them do nothing but watch them. All your trying to do at this point is to actually stop and simply watch what your mind is doing. Probably the easiest exercise in the whole system.