1997 Radio in 1992 Maxima

If you're not comfortable using a multimeter and a speaker popper/tester then you might want to consider taking the vehicle to a shop to have it installed.  Depending on what your maxima's factory system was like, it may or may not be a lot of extra work.

You'll need at the very least a '95-up Nissan reverse harness ( Metra 71-7550 or equivalent) to plug in to the new radio unit, and an '87-'94 regular Nissan harness ( Metra 70-1763 or equivalent) to plug in to your vehicle's wiring.  Not only is each wire on these two metra harnesses labeled with its function, but the colors will all match each other so you don't need to worry about a wiring diagram for the factory radio or anything like that.

If your vehicle does indeed have a factory amplifier for the rear speakers, you'll need to hook up the blue wire with a white stripe in the 70-1763 to the red wire of the 71-7550.  The reason I say this is because the '97 radio didn't necessarily come from a vehicle that had either a factory amplifier or a powered antenna, and so even though the 70-7550 harness has wires for these particular hookups, the '97 radio might not actually have anything in its own pinout that even connects to those pins.  It will definitely have a connection to the red wire though, and this wire is fine to use to turn on a factory amplifier that may be present in your vehicle.

It's possible that your vehicle has a different kind of antenna system from that meant to be used for the '97 radio.  If the '97 radio has a diversity (two-pin) type antenna and your vehicle has a standard motorola type antenna, then you'll need to get a nissan reverse antenna adapter.  Or on the other hand, if your vehicle uses a diversity type antenna but the '97 radio uses a standard motorola type antenna, a regular nissan antenna adapter will be required.