The oil pressure switch should be behind the intake manifold more
towards the drivers side.
If you pull off the plastic engine shield you might be able to see it easier.
You will also need a special deep socket designed for the sensor to remove it.
It screws into the engine block,not the intake.
You might be able to rent the tool from autozone(or similar store).
Unplug sensor and the sensor unscrews counter clock wise.
Be careful not to over tighten because it could break off in to the block.