Sine is really important and something you should know well. If you have a graphing calculator, I would suggest plotting a bunch of [tex]A\sin(\omega t+\phi)+C[/tex] equations to see how the graph changes as the parameters change.
Sine itself can never get bigger than 1, and the things inside the sin can never change the height of the graph. [tex]\omega[/tex] and [tex]\phi[/tex], which go inside sin, only change the spacing and position with respect to the t axis. [tex]\omega[/tex] is the frequency, or how frequently the curve goes from top to bottom. [tex]\phi[/tex] just shifts it left and right on the time axis.
Since things inside sin don't change the height, that means only A and C can affect the position on the y axis. Since plain sin has a maximum value of 1, the maximum of A*sin will be whatver A is. Then if you add a C term, that just shifts the whole thing up or down on the y axis.
The frequency is [tex]\omega[/tex] itself, and the amplitude is A itself. There's no need to take the sin of anything or multimply anything. You're just identifying parameters in the equation.