I'm trying to build my CNC router 3m*1.3m, but i'm not sure what is the type of stepper motor i should pay, all my CNC body is Al. I need to bay 4 Stepper motors, 4 drivers, spindle, inverter, and i d

The size of the stepper motor is measured in holding torque, generally oz/in. You will determine the torque loads of your axes when selecting steppers. Once you know which stepper you need, the drivers and controller board are simple to pair with them.