Hello, bit of a long post, but there’s some tips on helping you get results with the demons, and improving your connection to them.
I’d suggest Archangels of Magick by Damon Brand if you want to experience the reality of יהוה (EE-AH-OH-EH). The archangel Metatron is “one step down” from יהוה (EE-AH-OH-EH), and by calling upon the archangels, you will come to know this quality of power. The book’s by the same group as Demons of Magick, so if that book vibes with you you’ll probably like this one too.
I don’t mean to start a fight, but in all honesty, there are more than a few people here who will tell you that יהוה (EE-AH-OH-EH) and the angels are cruel, evil, and out to get you. There is as much truth in this as when religious Christians say that demons are cruel, evil, and out to get you. It is dogma rooted in religious thinking, not direct experience with these spiritual beings.
You will learn infinitely more from your experiences with the spirits than you will from reading any book, including the one I mentioned. Any book, assuming it is of high quality, will only help set you in the right direction, and will give you the tools you need to begin your journey. If you allow the angels to guide you, and are persistent in your efforts, you will come to know them, that I can promise.
–
From the sounds of it, however, you may be more in the mood for demonic work at the moment. You mentioned that you were having troubles sensing the demons’ presence when you called upon them. This is absolutely OK. You do not need to be able to sense the spirits in order to get results. By performing the ritual as described, you most definitely made contact, even if it didn’t feel like it.
The demons want to help you, as it brings them great satisfaction when you delight in the results they bring you. I would suggest that you practice doing the first ritual, the Petition for Results, for some time. Get some results, and grow your confidence in the magick and the demons. You can sit in an airmchair and read all day, but nothing is as important as just doing magick.
–
One day, you will know that you are ready to attempt the second ritual, Connective Evocation. You are not calling down the demon to full visible manifestation, not yet, but this method will call the demon into your presence, and will form a strong psychic connection between you. This grants the potential for extensive communication, though again, practice is so important. Evocation is a skill, and like any other skill, you will improve with persistence, and a balance of study and practice.
Though the connection will not be as strong as an evocation, it is certainly still possible to receive a message from the demon through the petition method. After making your request and before you close the ritual, spend a few minutes gazing at the demon’s seal, perhaps repeating their name occasionally. Take note of any thoughts that appear or moments of intuition, as the demon will attempt to communicate with you. Look back over these notes occasionally, to help you learn how the communication feels, and to see how the demon may have helped guide you.
–
If I may, there are also a few demons I would suggest for assisting your magick. Vine can “improve your ability to work with all forms of magick,” and Furcas can “increase your psychic abilities” as well as “improve your ability to trust your intuition.” If you call upon these demons for this purpose, I would treat it like a long-term investment. There may be noticeable effects right off the bat, but know that they will continue to expand over time. You may find it useful to call upon them every so often as well, to gradually improve your abilities.
Feel free to PM me any questions, always happy to help 
