Location of spark plugs and size? What type plug is recommended for this vehicl?

Obtain spark plugs from your Hyundai dealership for best results. And coils as needed also. But before you do that -- check the vehicle properly -- or have a diagnostic test performed. You very well could be chasing a concern that will cost you tons to attempt to repair via the "trial and error" method. Typically, if someone is asking where the spark plugs are, I automatically suggest seeking professional guidance.