95 milli S spark plugs and wires.. How the #$%!

I have a 95 Millenia S. Latley it is running rough. The check engine light came on also. Diagnosis shows it missing on cyl 3. and need a tune up bad. But I am dumbfounded on how to change these ($15 a piece) plugs. Anyone with a diagram or any info on how to do this please let me know. And any info on good deals on the plugs and whys would be a life saver.