Transient stress response acoustic silicon membrane

Hi all, I am new to COMSOL. I have already performed eigenfrequency analysis of a 2D silicon plate clamped at both ends vibrating in air. I now want to simulate the transient response of the motion by exciting the plate with a ultrasonic source close to the resonant frequency incident on the plate from top (in air). Is there a tutorial for this exercise available? I have doubts on how to correctly defining a sinusoidal excitation, and set the appropriate solver settings for this.