Sine function and finding average, max values

I've tried every way I know and I just can't figure this out, yet I was never good at this as it was never explained throughly to me, so I really need help, I can't seem to find anything that explains the process to me of how to find average values.(Doh)

The given: A sine function y=f(x) has a period of 8 and amplitude of 3. The minimum value of the function is f(2)=-1.

Now, I need to find the average values of this function, three values of x such that f(x)=average value, the maximum value, and three values of x such that f(x)=average value.

Any help would be appreciated, maybe something will jog my memory on this! Thanks.