'Kinematics - Vector Derivative' Exercise

I'm studying for a Mechanics exam and I have a doubt on a 'Kinematics - Vector Derivative' exercise. I don't know how to begin and that's my main problem.

Well, this is the exercise:



Some data:

This mechanical system comprises:

- Body 1: A T-shaped arm, with mass 'm', that rotates around the vertical axis Z0 with constant angular velocity 'theta point'.

- Body 2: A cursor with mass 'm2' which moves along the arm OC, being linked to O by a spring of stiffness 'K'

- Body 3: A arm with mass 'm3', articulated in C with Body 2, and that rotates around the axis Y2 with angular velocity 'fi point' and angular aceleration 'fi 2 points'.

Find out:

a) The absolute velocity and aceleration of the point C using the vector derivatives expressed in S2.
b) The absolute velocity and aceleration of the point G3 using the vector derivatives expressed in S2.
c) The absolute velocity and aceleration of the point C using the vector derivatives expressed in S3.
d) The absolute velocity and aceleration of the point G3 using the vector derivatives expressed in S3.

Can someone explain me how to start?

Thanks a lot!