Deism: Belief in a supreme God on the basis of reason and observation alone, without reference to divine revelation.
To explore some of the implications of this position, you might want to consult one or more of the pages listed below.
Except for the 2 articles from the Internet Encyclopedia of Philosophy (which are also perhaps a bit more detailed than one would want for an initial introduction), these are advocacy sites; and except for the article from the Catholic Encyclopedia, the advocacy is for deism and against what the writers define as its alternatives. That should not make them any the less useful in enabling you to see what the issues are on which deism takes the stances that historically define it.
Deism defined by the World Union of Deists.
Deism: the god that got away (at the website of Ontario Consultants on Religious Tolerance).
Deism: article from the Catholic Encyclopedia.
Two articles from the Internet Encyclopedia of Philosophy:
A History of Deism by Terry Matthews (United Deist Community website).
Deism / Age of Reason Forum: Offers resources on American Deism.
Deism and Reason: An advocacy site; offers definitions by several writers; compares and contrasts deism with other religious outlooks and with atheism.