I have a question on finding an expression on a sine wave could anybody point me in the right direction?

I know that the expression is y(x,t)=Asin(kx - wt + phi). The other information I have is A=0.5cm, wave length = 2cm and the phase of the wave at t=0 and x=0 is pi/2. which bits out of the above equation do I omit for the phase of the wave pi/2. Thanks in advance