Understanding the difference between CAN IDs and PIDS on OBD-II

I am trying to understand the CAN protocol for reading the diagnostic information from a car. For example, I know that on the car I am working on uses CAN identifier 0x7E0 as a query and 0x7E8 is the response sent back.

I am using a Vector GL1000 logger, and I am writing the code for this. The GL1000 uses a C-like language, and for me to retrieve information it uses the following format:

VAR Variable1 = CAN1 DATA (can-id) [bitA bitB] 

And for example if I wanted to retrieve the engine coolant temperature, the PID is: 05.
I understand my variable will look like so:

VAR Variable1 = CAN1 Data 0x7E0 (or is it 0x7E8?) [ bitA bitB]

I am stuck, because I don't know if I should use the query or the response CAN ID, and I don't know what bitA & bitB should be if I want to retrieve the engine coolant temperature.

I know this is far fetched, but Vectors IT cannot help me. Is there a way I can clarify such a far fetched question?