beeksc1,
The answer is that it depends on the particular Satanist. For example, there are some Satanists who are materialists who believe this life is all there is, that there is no G_d, no Devil and no afterlife; therefore, there is ultimately no right and wrong, no post-mortem consequences of actions and pleasure is all that really matters because this is it. These type of Satanists are basically just using "Satan" as an arch-type for human nature or as an attention-getter, e.g., Anton LaVey made a very profitable atheistic religion centered around this belief.
The other kinds of Satanists, the ones who actually believe in Satan as an existent being, have many different beliefs that
generally evolve from Christian theology. There are some who believe, for example, that Satan is actually the good guy, that G_d is not the true G_d or creator, but a lesser being who created the material world (as per Gnosticism). Yaweh is seen as a false god while Lucifer as the bringer of [the] light [of knowledge]. Then there are those who see Satan as the personification of forces such as chaos, evil, sensual desire, etc.
As a side note, an interesting example of an atypically positive view of Satan can found in the Yezidis' religion. The Yezidis essentially consider Melek Taus (i.e., Shaytan) to be a benevolent angel, often represented as a peacock, who, along with six other angels, is said to have been tested by G_d. However, as Melek Taus was the only angel to pass G_d's test by refusing to worship Adam and extinguishing the fires of Hell with his tears, G_d made Melek Taus the chief of all angels and the caretaker of creation (
Information about the Yezidi Kurds).
Jason