Python to Raspberry Pi to Seeduino to DC Brushless Motor?

Hello,

I'm new to Arduinos and Motors and PWM.
I was wondering if someone could give me a hint on how I can control a dc Brushless motor (3 wires) with my seeduino and Raspberry Pi??

If you guys could provide with some steps and sources to how I can get the motor to start spinning.... It's a pretty big motor, about the size of an adult mens arm so I'm not sure if I'll need an external power supply and if so how I can do that?

Wiring/coding etc.

Thank you very much in Advance for any help!

Is this an RC brushless motor without hall-sensors? If so then you need an ESC and use the Servo library to control it.

pretty big motor, about the size of an adult mens arm so I'm not sure if I'll need an external power supply

The arduino should be asked to supply no more than 40mA from an output pin.do you expect a motor that size to take that little current?
Yes you need an external supply and driver.