I'm assuming the question is how to run the same simulation multiple times for different frequencies. With this assumption ....
2. Double click the Sine Wave block, set the Amplitude parameter to 3, set the Frequency parameter to: freqHz*2*pi (enter it exactly that way).
3. In the Matlab workspace, or in a script, implement
for ii = 1:numel(freqvec)
Depending on what you're actually doing, the model and/or the code above might have to be modified, but this should be enough to give the basic idea.
I believe there is also a doc page that explains alternatives methods for running multiple simulations for a parameter sweep.