Particle Movement through space #3

A particle moves according to a law of motion s = f(t), t >= 0, where t is measured in seconds and s in feet.

Find the velocity at time t.

What is the velocity after 3 s?

When is the particle at rest?

When is the particle moving in the positive direction?

Find the total distance traveled during the first 8 seconds.

Find the acceleration at time t after 3 s.

When is the particle speeding up? When is it slowing down?

The Equation is: f(t)= cos(πt/4), t <= 10

I don't quite understand how do to this problem so a complete explanation would be best.