I've studied different flavors of Satanism depends on their belief system and see Satan as with yourself or an actual being outside of the self.LaVeyan, Theistic/SpiritualLuciferianism, Anti-Cosmic Tradition, Order of the Nine Angles,and their is another tradition where you mix Lord and Lady Death into Satanism.
As a chaoteI see Satan like I see his twin Yahweh or whichever names they go by. Also symbolism of anti-creation and one of the gatekeepers of the abyss.
Www.joyofsatan.com it's a great website to learn as well as The Church of Satan.Both are great tools and can give you a solid foundation on what Satanism is.
I've studied some Satanism and quite a bit on Demons. Demons were once Gods in ancient civilizations and to various cultures before the Abrahamic faiths came into the picture and they were Demonized. A good example would be Astaroth who was known as Astarte and Inanna in different regions.
It is important to know that Satanism is not a religion of evil. It is a religion of spiritual growth and personal power.
I recommend that you check out the follwoing YouTube Channels as they're quite informative:
Indigo Priestess, Damon Dark, Black Magick Exposed, EA Koetting and Black Witch Coven
Most importantly, learn how to shield and when working with Demons show respect.
even though truth is personal a true seeker of truth is one who is a researcher in diffreant philosophies,scientific studies and ancient or modern religion..a real satanist is a researcher and a seeker of truth,the "sheep" mentality is forbiden in satanism and you can only believe that which makes sense to you..i know some may be against but the fact is that there is truth and error and when we say this is the truth we are acknowledging the fact that there is such thing as falsehood..in a certain sense truth is personal, but there is also universal truth.