I feel kind of overwhelmed by it, and would like someone to walk me through the steps of sketching the signal.
From your physics knowledge you get that sine waves are usually equated, in the general case, as
$$y(t) = A * \sin(\omega t)$$
where $\omega = 2 \pi f$ and the periodicity is $T=1/f$
Comparing the general equation with your particular case, you have: $$2*\pi*f = \pi / 4$$ meaning that $$f=1/8 Hz$$ or $$T=1/f=8s$$ The amplitude is $A=3$
If you want to plot it in matlab, for example, just write
t = 0:0.01:16; x = 3*sin(pi*t/4); plot(x,t)
As a final comment, this is really a basic question and you should carefully read your textbook if you want to progress to more advanced topics.