Protestants beliefs follow the same book at the Catholics. The Schism of 1604 caused the divide between the Catholics and the Protestants because the Catholics had a more rigid form to their religious practices where as the protestants were a bit more liberal in their beliefs.
All Protestants believe in baptism, communion and confirmation. A difference from Catholics is that Protestants don't believe in the transformation of bread and wine into flesh and blood during communion.
Any Christian denomination that is not Roman Catholic is considered Protestant. They believe that doctrine comes from scripture, salvation is through grace alone, and sins are forgiven by Christ alone.
Protestants are too varied in practice and scope to discuss common beliefs. They are "protestant" because they came out of the reformation churches that "protested" against the Catholic church.
The major difference between protestant Christians and Catholics is that they believe the only way to receive salvation is through faith, and not acts as believed by Catholics.