Use the Convolution theorem to calculate the Fourier Series, then write x(t) as a weighted sum of cosines

The convolution theorem for the Fourier Transform is:

$$y(t) = h(t)*x(t) leftarrow rightarrow Y(jw) = H(jw)X(jw)$$

The given $$x(t)$$ is $$x(t)=cos^3(t)$$. No $$h(t)$$ was given.

I don’t really know how to use the convolution theorem to get to the Fourier Series. Can anyone help me?