1991 Toyota Corolla How to remove&replace a water pump

Best thing to do is to use the car repair link in this thread or get a Haynes manual.

On the 4AFE engine you will have to loosen the motor mounts and raise the engine to get the WP pulley off, because it is so close to the body.

You will have to remove the timing belt, or drain all the coolant including the block so as not to contaminate the timing belt, also mark rotation of belt if you intend to reuse.

There is also a hose from the rear of the WP to the thermostat housing. This would be a good time to replace it.

The manual will give you step by step instructions, and will pay for itself the first repair.