The captain's failure to maintain situational awareness, which resulted in the airplane being outside the confines of the instrument approach; and the crew's misinterpretation of a step-down fix passage, which resulted in an early descent into rising terrain. Factors included the captain's misreading of the instrument approach procedure, the crew's rushed and incomplete instrument approach briefing, their failure to use additional, available navigational aids, and their failure to account for the winds at altitude.