calculate $\Phi^{*}\omega \;$ for a given $\omega$

Question

so we have :

$$\Phi : \mathbb{R}^3\rightarrow \mathbb{R}^3$$

$$(x,y,z) \mapsto (xy,yz^2,z^3)$$

How can I calculate $\Phi^{*}\omega \; $ for :

i) $\omega= x\,dx\wedge dz - dx\wedge dy$

ii) $\omega= x\,dx\wedge dy \wedge dz$

Any help would be appreciate thanks in advance.