It is my pleasure to try and help where I may.
I have a couple of personal reasons why I use the Headless. One is that it is a VERY old magical ritual of invocation and exorcism. It releases you from any spirit that may be binding you, infuses you with power and elevates the mind. It is also made to grant you your daemon or what some call the HGA which you could even think of it as filling you with a divine current. I recommend it if you are familiar with and agree with some of the forces in it. You should try and read up on it as much as you can to see if the forces it calls upon are in agreement with you. I have a good friend who is a fantastic ceremonial magician who does not want to go near it because of the Sethian influences. He is more into placing the kabbalistic divine names in the parts of the body.
I recommend reading The Chaos Protocols by Gordon White as he explains the shamanistic roots of the rite as well as the Orion connections.
Jake Stratton-Kent has a great book on it outlining the more Sethian aspects and the Kundalini work Crowley did with it (which is one of my basic day to day use of it.)
For other studying read up on Gnosticism, Aion, Achrons, IAO, Orion mythology, and Prajapati.
Visualization wise is where we can run into some speed bumps. I don’t know what modalities would work best for you, where your ability at concentration is, what system calls to you, what your spirituality is, etc. Generally speaking you would do fine with the Temperance/Art card to stand in for your HGA (hence Liber Samekh) and also researching everything there which could lead to some insights. If you already have a symbol or image that is a stand in for the idea of “Lord” or your angel, or whatever you conceive of as the force that put all of this together and keeps it this way, then that should be the main visualization. I could give you mine but, that may not do at all for you. If no such image exists then go with Orion, imagine from the point in the sky the constellation is in that you are calling directly to him with the spell. Try and imagine Orion comes closer and closer as the spell moves on and when you reach the point where you speak as the deity than imagine you merge with Orion as you would any god-form (if unfamiliar with that check out the Golden Dawn and how they describe the assumption of a God-Form and fit it to need here).
As you can see there can be a lot of variables and variables within variables. Hence, read up and once you feel knowledgeable in its origin and use, just do it. Worse thing that can happen is you realize reality is not as solid as you previously assumed and now you have this weird energetic buzz surrounding you.