In this pic:
The TPS is the bottom of the two sensors you see in the far right pic. Just above and behind the water outlet. The TPS is the lowest sensor on the Throttle Body. The pivot shaft for the butterfly (throttle plate) points right at it.
Best way to change it is to get a throttle body gasket, remove the TB, and follow these instructions to clean the TB and the MAF sensor, then install the new TPS and reassemble. Your car will probably benefit greatly from the attention:
After you install the TPS, make sure the small pin on the throttle shaft is on the curved face of the arm of the sensor. Before installing everything, make sure that arm moves when you actuate the throttle. It is possible to get the arm on the wrong side.