it is the same as the OAT written (i.e same order of sections, same level of difficulty)
you are given a brief tutorial before you begin you testing session (ie---how to go through the test using keypad/mouse); you are also given scrap paper for any calculations (which has to be returned after the testing session)
a great study aide that helps you get acquainted with the computerized format is the "Topscore OAT Score guide" ---it is a CD that has 3 different OAT tests and allows you the option of having them timed (as in an actual test situation)---the CD is between $45-50
good luck!