Really simple Cliff. Unfortunately, it's the whole bumper cover.

In the wheel openings, a 1mm hex bolt, one per side. If the bracket won't come loose from the bumper, you can remove the bracket from the car side instead.

In front, where you'd expect frame-tips, there are two 13mm hex bolts on each side (just under the fog-lamp IIRC). Accessible from beneath the bumper.

Center, one bolt top/center, not sure if it's 10mm or 13mm. Accesible with the hood up.

Last is the temp-sensor (first really), behind the license-plate bracket. To the car's right of center on the front section, there is a recessed phillips screw that needs to be removed to release the temp sensor so that it can remain on the car. Early ('86/'87) has this sensor on the driver's side of the bumper, yours is centered.

When you have the bumper off, unless you are buying a complete/used one, you will want to save the tow-hook cover on the right side, the license-plate bracket (or filler panel), and the rub-strip.

The tow-hook cover un-clips at the top, the rest is obvious.

License-plate mount on the '90 should have screws you can see, then slide upward out of the bracket behind it. Remove the bracket also.

The rub-strip has three phillips screws in each end from the inside of the bumper, and tabs around the rest of the top & bottom, pry the center of the tab inward from behind the bumper to release them one-by-one.

Good luck, biggest pain is painting the new bumper-cover to match. I've had to replace the one on my daughter's '94 three times, ...

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