1998 Ford Courier sensor help plz

I did step 1 with getting a system diagnostic test for check engine light. Now step 2. My dad is changing the sensors for me. The codes on the report was po136 and po156 which is the sensor b152 and b2-52. After also replacing the starter, my dad noticed a sensor next to the thermostat and starter which the sensor connects to the manifold. He thinks that is a heat sensor but not sure, is it?And not sure where the bank 1 and 2 sensor is. Supposedly there are 4 or 2 of each, have no idea. Where would these bank sensors be and how to get to it. Also, how many sensors are there in total. Are there any important ones to check out. If so, of course id say where would it be, im clueless. Thank you, you have been helpfull. Ill fill you in after this is all done. My car has many problems thankx :)