First, be sure tu use the battery, the USB doesn't deliver power to the motors. The servos aren't connected directly to the processor (the Atmel 32 chip), but to a multi-PWM driver (PCA9885 chip). If you think in terms of Arduino board, the motors aren't connected to the PWM pad of the Arduino (pins 9 /10 for UNO) but to a servo shield. So you can't use the Servo.h library, you have to use some dedicated library, such as Adafruit_PWMServoDriver.h which appears in the OpenCat sources. I don't know if this answer makes sense to you. It will depend on your background. I can elaborate more and/or write an example if you need.

Do you mean I don't know how to press a button ? Well, you're right :) I though the blue light indicated some 'ON' status, but I wasn't pressing long enough. Thank you (I feel somewhat stupid now but I can handle that)