I am a bit confused on what requirements i need to look for if I want to power the driver with a wall power supply. Do I just select a 12V, but what about the amp.
According to the specification, the motor driver can provide up to 30A in peak current.
The motor will consume a maximum of 3.6A in torque stall (blocked).
The motor driver can control any motor from 5V to 30V. Since you are using a 12V motor, then you need to supply 12V to the driver.
You no need to care about the amp, it is fluctuant. It depends on how much your motor consumes and how much your power supply (the battery) can supply.
It is not advised to use the wall power supply to power this type of motor driver. You should use a battery instead.