Hyundai Repair: rear driver side strut, spring compressor, seat back

Question
where is the bracket holding the strut on 2000 Elantra

Answer
Sorry for taking so long, Dawn.  I wanted to look in the illustration in the shop manual because I cannot recall replacing one of these.  

From the diagram in the shop manual, it appears that the upper strut mounting nuts (3) are in the trunk, but it's not clear whether you'd acccess from the trunk or by removing the rear seat back side bolster.  I'd recommend checking in the trunk first, since I'm sure it's easier to pull the trim back and have a look if necessary than to remove the bolster.

The bottom of the strut attaches to the knuckle.

Also, if you're not completely familiar and comfortable with what you're doing, this is a job better left to a professional.  The spring has a significant amount of energy stored in it, and you'll need a spring compressor to remove the strut from the spring.  If you take the wrong thing loose or the spring comes out of the compressor, it can hit you with enough force to kill you.