How do you replace the fan belts in a 1991 Nissan Maxima?

there is one question that needs to be answered by you first.........add it here as an improvement............which engine does you car have,starting in late 91 Nissan offered 2 different motors.......to tell look at the little aluminum plate attached to the firewall in the engine compartment its apx 1 1/2 by 1 1/2 it will say vg30e or vg30de.i know and have done my vg30e motors belts .look on my bio page ive given imfo on this subject.............................buddy mack