Answer
amplitude: $3$
period:$\dfrac{\pi}{2}$
Work Step by Step
If a function has form $y=A\sin(\alpha x)$, then there $|A|$ stands for the amplitude and $T =\frac{2\pi}{\omega}$ stands for the period.
Hence, here we have
$|A|=|3|=3$
$\omega=4$, thus $T=\dfrac{2\pi}{4}=\dfrac{\pi}{2}$