i am supposed to find the equation for this graph, (attached)

in the form of f(x)= asin(bx+c)

i have the hardest time at drawing graphs. i know how to find the amplitude (which is 2 here) and i know that the period=2pi/B (so the period is pi here. but i cant seem to figure out how to find the phase shift or how to draw the entire graph from just an equation. does anyone have any tips?