2004 hyundai santa fe shift lock release

2004 Hyundai Santa Fe, automatic transmission, 167K miles.

This is just the latest in a multitude of problems. After getting a new battery put in last week, I drove it about 30 miles, parked, and turned the car off. I had some trouble moving the gear shift into park when turning the car off, seemed like it was resisting. An hour later, when I tried to turn the car back on, it wouldn't start. All the accessories would turn on, but the starter wasn't even making any sort of clicking noise. A friend suggested shifting the car into neutral and it started. Had some trouble shifting into Drive, but once it is in Drive, it runs just fine. Stopped to check the transmission fluid, which looked full (maybe too full?). Was able to get it home, then the next day planned to drive it to my mechanic, but couldn't get it into Drive - again, starting in neutral. So the lights on the dashboard are not recognizing the gear shift being in Park, even though the shift lock button must be pushed to get it out of the park position. Also not able to get it in Drive. Don't know if this is an electrical problem, something is preventing the gear shift from moving, transmission issue, or something else entirely. Any help would be appreciated. Thanks in advance.

Update: Took it to the mechanic. "Removed shift cable and cleaned shifter shaft. Readjust transmission switch and re-installed cable." covered in rust. they cleaned it off and i didn't have to get a new one! only $110 for labor.

Where is the shift lock release button?