I need to know where the heater core is and.

Under the passenger side dash.
1. Disconnect the negative battery cable.
2. Remove the air cleaner and duct assembly.
3. Drain and recycle the engine coolant.
4. Disconnect the wiper linkage from wiper motor.
5. Detach both heater hoses at the heater core.
6. Remove the lower center console.
7. Remove both instrument panel insulators.
8. Remove the heater outlet module screws, and heater cover.
9. Remove the heater core mounting clip screw, and the heater core line clamp screw.
10. Carefully pull the heater core from the case.
11. If necessary, remove the foam seals on the heater core module for transfer to the replacement core.
12. If necessary, remove the heater core line clamp for transfer to the replacement core.

You must disconnect the wiper linkage to allow clerance for removing the heater core coolant hoses.
This info is from my database, if you see a better way, go for it, use your own initiative.