How do I remove the heat shield and replace spark plug on front driver side?

 

Pull back the carpet and you will find the bolt head and using a wrench and socket you can unmount the heat shield.

On my 97 I don't even bother to remove the heat shield. I just move it enough to get the spark plug socket in and on the plug.

 

Do you mean the large silverish heat shield attached to the body, or the round shield around the spark plug?