complex numbers - Finding modulus of $sqrt{6} - sqrt{6},i$

I found the real part $=\sqrt{6}$.

But I don't know how to find imaginary part. I thought it was whatever part of the function that involved $i$, with the $i$ removed? Therefore the imaginary part would be $-\sqrt{6}$.

Meaning the modulus is equal to

$$\begin{align} \sqrt{ (\sqrt{6})^2 + (-\sqrt{6})^2} = \sqrt{12}. \end{align}$$
The answer was $2\sqrt{3}$.